[PM-27123] Account Credit not Showing for Premium Upgrade Payment (#6484)

* feat(billing): add PaymentMethod union

* feat(billing):  add nontokenized payment method

* feat(billing): add validation for tokinized and nontokenized payments

* feat(billing): update and add payment method requests

* feat(billing): update command with new union object

* test(billing): add tests for account credit for user.

* feat(billing): update premium cloud hosted subscription request

* fix(billing): dotnet format

* tests(billing): include payment method tests

* fix(billing): clean up tests and converter method

src/Api/Billing/Attributes/NonTokenizedPaymentMethodTypeValidationAttribute.cs

@@ -0,0 +1,13 @@
+using Bit.Api.Utilities;
+
+namespace Bit.Api.Billing.Attributes;
+
+public class NonTokenizedPaymentMethodTypeValidationAttribute : StringMatchesAttribute
+{
+    private static readonly string[] _acceptedValues = ["accountCredit"];
+
+    public NonTokenizedPaymentMethodTypeValidationAttribute() : base(_acceptedValues)
+    {
+        ErrorMessage = $"Payment method type must be one of: {string.Join(", ", _acceptedValues)}";
+    }
+}

src/Api/Billing/Attributes/TokenizedPaymentMethodTypeValidationAttribute.cs

@@ -2,11 +2,11 @@
 
 namespace Bit.Api.Billing.Attributes;
 
-public class PaymentMethodTypeValidationAttribute : StringMatchesAttribute
+public class TokenizedPaymentMethodTypeValidationAttribute : StringMatchesAttribute
 {
     private static readonly string[] _acceptedValues = ["bankAccount", "card", "payPal"];
 
-    public PaymentMethodTypeValidationAttribute() : base(_acceptedValues)
+    public TokenizedPaymentMethodTypeValidationAttribute() : base(_acceptedValues)
     {
         ErrorMessage = $"Payment method type must be one of: {string.Join(", ", _acceptedValues)}";
     }

src/Api/Billing/Models/Requests/Payment/MinimalTokenizedPaymentMethodRequest.cs

@@ -7,7 +7,7 @@ namespace Bit.Api.Billing.Models.Requests.Payment;
 public class MinimalTokenizedPaymentMethodRequest
 {
     [Required]
-    [PaymentMethodTypeValidation]
+    [TokenizedPaymentMethodTypeValidation]
     public required string Type { get; set; }
 
     [Required]

src/Api/Billing/Models/Requests/Payment/NonTokenizedPaymentMethodRequest.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations;
+using Bit.Api.Billing.Attributes;
+using Bit.Core.Billing.Payment.Models;
+
+namespace Bit.Api.Billing.Models.Requests.Payment;
+
+public class NonTokenizedPaymentMethodRequest
+{
+    [Required]
+    [NonTokenizedPaymentMethodTypeValidation]
+    public required string Type { get; set; }
+
+    public NonTokenizedPaymentMethod ToDomain()
+    {
+        return Type switch
+        {
+            "accountCredit" => new NonTokenizedPaymentMethod { Type = NonTokenizablePaymentMethodType.AccountCredit },
+            _ => throw new InvalidOperationException($"Invalid value for {nameof(NonTokenizedPaymentMethod)}.{nameof(NonTokenizedPaymentMethod.Type)}")
+        };
+    }
+}

src/Api/Billing/Models/Requests/Premium/PremiumCloudHostedSubscriptionRequest.cs

@@ -4,10 +4,10 @@ using Bit.Core.Billing.Payment.Models;
 
 namespace Bit.Api.Billing.Models.Requests.Premium;
 
-public class PremiumCloudHostedSubscriptionRequest
+public class PremiumCloudHostedSubscriptionRequest : IValidatableObject
 {
-    [Required]
-    public required MinimalTokenizedPaymentMethodRequest TokenizedPaymentMethod { get; set; }
+    public MinimalTokenizedPaymentMethodRequest? TokenizedPaymentMethod { get; set; }
+    public NonTokenizedPaymentMethodRequest? NonTokenizedPaymentMethod { get; set; }
 
     [Required]
     public required MinimalBillingAddressRequest BillingAddress { get; set; }
@@ -15,11 +15,38 @@ public class PremiumCloudHostedSubscriptionRequest
     [Range(0, 99)]
     public short AdditionalStorageGb { get; set; } = 0;
 
-    public (TokenizedPaymentMethod, BillingAddress, short) ToDomain()
+
+    public (PaymentMethod, BillingAddress, short) ToDomain()
     {
-        var paymentMethod = TokenizedPaymentMethod.ToDomain();
+        // Check if TokenizedPaymentMethod or NonTokenizedPaymentMethod is provided.
+        var tokenizedPaymentMethod = TokenizedPaymentMethod?.ToDomain();
+        var nonTokenizedPaymentMethod = NonTokenizedPaymentMethod?.ToDomain();
+
+        PaymentMethod paymentMethod = tokenizedPaymentMethod != null
+            ? tokenizedPaymentMethod
+            : nonTokenizedPaymentMethod!;
+
         var billingAddress = BillingAddress.ToDomain();
 
         return (paymentMethod, billingAddress, AdditionalStorageGb);
     }
+
+    public IEnumerable<ValidationResult> Validate(ValidationContext validationContext)
+    {
+        if (TokenizedPaymentMethod == null && NonTokenizedPaymentMethod == null)
+        {
+            yield return new ValidationResult(
+                "Either TokenizedPaymentMethod or NonTokenizedPaymentMethod must be provided.",
+                new[] { nameof(TokenizedPaymentMethod), nameof(NonTokenizedPaymentMethod) }
+            );
+        }
+
+        if (TokenizedPaymentMethod != null && NonTokenizedPaymentMethod != null)
+        {
+            yield return new ValidationResult(
+                "Only one of TokenizedPaymentMethod or NonTokenizedPaymentMethod can be provided.",
+                new[] { nameof(TokenizedPaymentMethod), nameof(NonTokenizedPaymentMethod) }
+            );
+        }
+    }
 }

src/Core/Billing/Payment/Models/NonTokenizedPaymentMethod.cs

@@ -0,0 +1,11 @@
+namespace Bit.Core.Billing.Payment.Models;
+
+public record NonTokenizedPaymentMethod
+{
+    public NonTokenizablePaymentMethodType Type { get; set; }
+}
+
+public enum NonTokenizablePaymentMethodType
+{
+    AccountCredit,
+}

src/Core/Billing/Payment/Models/PaymentMethod.cs

@@ -0,0 +1,69 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using OneOf;
+
+namespace Bit.Core.Billing.Payment.Models;
+
+[JsonConverter(typeof(PaymentMethodJsonConverter))]
+public class PaymentMethod(OneOf<TokenizedPaymentMethod, NonTokenizedPaymentMethod> input)
+    : OneOfBase<TokenizedPaymentMethod, NonTokenizedPaymentMethod>(input)
+{
+    public static implicit operator PaymentMethod(TokenizedPaymentMethod tokenized) => new(tokenized);
+    public static implicit operator PaymentMethod(NonTokenizedPaymentMethod nonTokenized) => new(nonTokenized);
+    public bool IsTokenized => IsT0;
+    public bool IsNonTokenized => IsT1;
+}
+
+internal class PaymentMethodJsonConverter : JsonConverter<PaymentMethod>
+{
+    public override PaymentMethod Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        var element = JsonElement.ParseValue(ref reader);
+
+        if (!element.TryGetProperty("type", out var typeProperty))
+        {
+            throw new JsonException("PaymentMethod requires a 'type' property");
+        }
+
+        var type = typeProperty.GetString();
+
+
+        if (Enum.TryParse<TokenizablePaymentMethodType>(type, true, out var tokenizedType) &&
+            Enum.IsDefined(typeof(TokenizablePaymentMethodType), tokenizedType))
+        {
+            var token = element.TryGetProperty("token", out var tokenProperty) ? tokenProperty.GetString() : null;
+            if (string.IsNullOrEmpty(token))
+            {
+                throw new JsonException("TokenizedPaymentMethod requires a 'token' property");
+            }
+
+            return new TokenizedPaymentMethod { Type = tokenizedType, Token = token };
+        }
+
+        if (Enum.TryParse<NonTokenizablePaymentMethodType>(type, true, out var nonTokenizedType) &&
+            Enum.IsDefined(typeof(NonTokenizablePaymentMethodType), nonTokenizedType))
+        {
+            return new NonTokenizedPaymentMethod { Type = nonTokenizedType };
+        }
+
+        throw new JsonException($"Unknown payment method type: {type}");
+    }
+
+    public override void Write(Utf8JsonWriter writer, PaymentMethod value, JsonSerializerOptions options)
+    {
+        writer.WriteStartObject();
+
+        value.Switch(
+            tokenized =>
+            {
+                writer.WriteString("type",
+                    tokenized.Type.ToString().ToLowerInvariant()
+                );
+                writer.WriteString("token", tokenized.Token);
+            },
+            nonTokenized => { writer.WriteString("type", nonTokenized.Type.ToString().ToLowerInvariant()); }
+        );
+
+        writer.WriteEndObject();
+    }
+}

src/Core/Billing/Premium/Commands/CreatePremiumCloudHostedSubscriptionCommand.cs

@@ -16,6 +16,7 @@ using Microsoft.Extensions.Logging;
 using OneOf.Types;
 using Stripe;
 using Customer = Stripe.Customer;
+using PaymentMethod = Bit.Core.Billing.Payment.Models.PaymentMethod;
 using Subscription = Stripe.Subscription;
 
 namespace Bit.Core.Billing.Premium.Commands;
@@ -38,7 +39,7 @@ public interface ICreatePremiumCloudHostedSubscriptionCommand
     /// <returns>A billing command result indicating success or failure with appropriate error details.</returns>
     Task<BillingCommandResult<None>> Run(
         User user,
-        TokenizedPaymentMethod paymentMethod,
+        PaymentMethod paymentMethod,
         BillingAddress billingAddress,
         short additionalStorageGb);
 }
@@ -60,7 +61,7 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
 
     public Task<BillingCommandResult<None>> Run(
         User user,
-        TokenizedPaymentMethod paymentMethod,
+        PaymentMethod paymentMethod,
         BillingAddress billingAddress,
         short additionalStorageGb) => HandleAsync<None>(async () =>
     {
@@ -74,6 +75,7 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
             return new BadRequest("Additional storage must be greater than 0.");
         }
 
+        // Note: A customer will already exist if the customer has purchased account credits.
         var customer = string.IsNullOrEmpty(user.GatewayCustomerId)
             ? await CreateCustomerAsync(user, paymentMethod, billingAddress)
             : await subscriberService.GetCustomerOrThrow(user, new CustomerGetOptions { Expand = _expand });
@@ -82,18 +84,31 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
 
         var subscription = await CreateSubscriptionAsync(user.Id, customer, additionalStorageGb > 0 ? additionalStorageGb : null);
 
-        switch (paymentMethod)
-        {
-            case { Type: TokenizablePaymentMethodType.PayPal }
-                when subscription.Status == StripeConstants.SubscriptionStatus.Incomplete:
-            case { Type: not TokenizablePaymentMethodType.PayPal }
-                when subscription.Status == StripeConstants.SubscriptionStatus.Active:
+        paymentMethod.Switch(
+            tokenized =>
+            {
+                // ReSharper disable once SwitchStatementHandlesSomeKnownEnumValuesWithDefault
+                switch (tokenized)
+                {
+                    case { Type: TokenizablePaymentMethodType.PayPal }
+                        when subscription.Status == StripeConstants.SubscriptionStatus.Incomplete:
+                    case { Type: not TokenizablePaymentMethodType.PayPal }
+                        when subscription.Status == StripeConstants.SubscriptionStatus.Active:
+                        {
+                            user.Premium = true;
+                            user.PremiumExpirationDate = subscription.GetCurrentPeriodEnd();
+                            break;
+                        }
+                }
+            },
+            nonTokenized =>
+            {
+                if (subscription.Status == StripeConstants.SubscriptionStatus.Active)
                 {
                     user.Premium = true;
                     user.PremiumExpirationDate = subscription.GetCurrentPeriodEnd();
-                    break;
                 }
-        }
+            });
 
         user.Gateway = GatewayType.Stripe;
         user.GatewayCustomerId = customer.Id;
@@ -109,9 +124,15 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
     });
 
     private async Task<Customer> CreateCustomerAsync(User user,
-        TokenizedPaymentMethod paymentMethod,
+        PaymentMethod paymentMethod,
         BillingAddress billingAddress)
     {
+        if (paymentMethod.IsNonTokenized)
+        {
+            _logger.LogError("Cannot create customer for user ({UserID}) using non-tokenized payment method. The customer should already exist", user.Id);
+            throw new BillingException();
+        }
+
         var subscriberName = user.SubscriberName();
         var customerCreateOptions = new CustomerCreateOptions
         {
@@ -153,13 +174,14 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
 
         var braintreeCustomerId = "";
 
+        // We have checked that the payment method is tokenized, so we can safely cast it.
         // ReSharper disable once SwitchStatementHandlesSomeKnownEnumValuesWithDefault
-        switch (paymentMethod.Type)
+        switch (paymentMethod.AsT0.Type)
         {
             case TokenizablePaymentMethodType.BankAccount:
                 {
                     var setupIntent =
-                        (await stripeAdapter.SetupIntentList(new SetupIntentListOptions { PaymentMethod = paymentMethod.Token }))
+                        (await stripeAdapter.SetupIntentList(new SetupIntentListOptions { PaymentMethod = paymentMethod.AsT0.Token }))
                         .FirstOrDefault();
 
                     if (setupIntent == null)
@@ -173,19 +195,19 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
                 }
             case TokenizablePaymentMethodType.Card:
                 {
-                    customerCreateOptions.PaymentMethod = paymentMethod.Token;
-                    customerCreateOptions.InvoiceSettings.DefaultPaymentMethod = paymentMethod.Token;
+                    customerCreateOptions.PaymentMethod = paymentMethod.AsT0.Token;
+                    customerCreateOptions.InvoiceSettings.DefaultPaymentMethod = paymentMethod.AsT0.Token;
                     break;
                 }
             case TokenizablePaymentMethodType.PayPal:
                 {
-                    braintreeCustomerId = await subscriberService.CreateBraintreeCustomer(user, paymentMethod.Token);
+                    braintreeCustomerId = await subscriberService.CreateBraintreeCustomer(user, paymentMethod.AsT0.Token);
                     customerCreateOptions.Metadata[BraintreeCustomerIdKey] = braintreeCustomerId;
                     break;
                 }
             default:
                 {
-                    _logger.LogError("Cannot create customer for user ({UserID}) using payment method type ({PaymentMethodType}) as it is not supported", user.Id, paymentMethod.Type.ToString());
+                    _logger.LogError("Cannot create customer for user ({UserID}) using payment method type ({PaymentMethodType}) as it is not supported", user.Id, paymentMethod.AsT0.Type.ToString());
                     throw new BillingException();
                 }
         }
@@ -203,18 +225,21 @@ public class CreatePremiumCloudHostedSubscriptionCommand(
         async Task Revert()
         {
             // ReSharper disable once SwitchStatementMissingSomeEnumCasesNoDefault
-            switch (paymentMethod.Type)
+            if (paymentMethod.IsTokenized)
             {
-                case TokenizablePaymentMethodType.BankAccount:
-                    {
-                        await setupIntentCache.RemoveSetupIntentForSubscriber(user.Id);
-                        break;
-                    }
-                case TokenizablePaymentMethodType.PayPal when !string.IsNullOrEmpty(braintreeCustomerId):
-                    {
-                        await braintreeGateway.Customer.DeleteAsync(braintreeCustomerId);
-                        break;
-                    }
+                switch (paymentMethod.AsT0.Type)
+                {
+                    case TokenizablePaymentMethodType.BankAccount:
+                        {
+                            await setupIntentCache.RemoveSetupIntentForSubscriber(user.Id);
+                            break;
+                        }
+                    case TokenizablePaymentMethodType.PayPal when !string.IsNullOrEmpty(braintreeCustomerId):
+                        {
+                            await braintreeGateway.Customer.DeleteAsync(braintreeCustomerId);
+                            break;
+                        }
+                }
             }
         }
     }

test/Core.Test/Billing/Payment/Models/PaymentMethodTests.cs

@@ -0,0 +1,112 @@
+using System.Text.Json;
+using Bit.Core.Billing.Payment.Models;
+using Xunit;
+
+namespace Bit.Core.Test.Billing.Payment.Models;
+
+public class PaymentMethodTests
+{
+    [Theory]
+    [InlineData("{\"cardNumber\":\"1234\"}")]
+    [InlineData("{\"type\":\"unknown_type\",\"data\":\"value\"}")]
+    [InlineData("{\"type\":\"invalid\",\"token\":\"test-token\"}")]
+    [InlineData("{\"type\":\"invalid\"}")]
+    public void Read_ShouldThrowJsonException_OnInvalidOrMissingType(string json)
+    {
+        // Arrange
+        var options = new JsonSerializerOptions { Converters = { new PaymentMethodJsonConverter() } };
+
+        // Act & Assert
+        Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<PaymentMethod>(json, options));
+    }
+
+    [Theory]
+    [InlineData("{\"type\":\"card\"}")]
+    [InlineData("{\"type\":\"card\",\"token\":\"\"}")]
+    [InlineData("{\"type\":\"card\",\"token\":null}")]
+    public void Read_ShouldThrowJsonException_OnInvalidTokenizedPaymentMethodToken(string json)
+    {
+        // Arrange
+        var options = new JsonSerializerOptions { Converters = { new PaymentMethodJsonConverter() } };
+
+        // Act & Assert
+        Assert.Throws<JsonException>(() => JsonSerializer.Deserialize<PaymentMethod>(json, options));
+    }
+
+    // Tokenized payment method deserialization
+    [Theory]
+    [InlineData("bankAccount", TokenizablePaymentMethodType.BankAccount)]
+    [InlineData("card", TokenizablePaymentMethodType.Card)]
+    [InlineData("payPal", TokenizablePaymentMethodType.PayPal)]
+    public void Read_ShouldDeserializeTokenizedPaymentMethods(string typeString, TokenizablePaymentMethodType expectedType)
+    {
+        // Arrange
+        var json = $"{{\"type\":\"{typeString}\",\"token\":\"test-token\"}}";
+        var options = new JsonSerializerOptions { Converters = { new PaymentMethodJsonConverter() } };
+
+        // Act
+        var result = JsonSerializer.Deserialize<PaymentMethod>(json, options);
+
+        // Assert
+        Assert.True(result.IsTokenized);
+        Assert.Equal(expectedType, result.AsT0.Type);
+        Assert.Equal("test-token", result.AsT0.Token);
+    }
+
+    // Non-tokenized payment method deserialization
+    [Theory]
+    [InlineData("accountcredit", NonTokenizablePaymentMethodType.AccountCredit)]
+    public void Read_ShouldDeserializeNonTokenizedPaymentMethods(string typeString, NonTokenizablePaymentMethodType expectedType)
+    {
+        // Arrange
+        var json = $"{{\"type\":\"{typeString}\"}}";
+        var options = new JsonSerializerOptions { Converters = { new PaymentMethodJsonConverter() } };
+
+        // Act
+        var result = JsonSerializer.Deserialize<PaymentMethod>(json, options);
+
+        // Assert
+        Assert.True(result.IsNonTokenized);
+        Assert.Equal(expectedType, result.AsT1.Type);
+    }
+
+    // Tokenized payment method serialization
+    [Theory]
+    [InlineData(TokenizablePaymentMethodType.BankAccount, "bankaccount")]
+    [InlineData(TokenizablePaymentMethodType.Card, "card")]
+    [InlineData(TokenizablePaymentMethodType.PayPal, "paypal")]
+    public void Write_ShouldSerializeTokenizedPaymentMethods(TokenizablePaymentMethodType type, string expectedTypeString)
+    {
+        // Arrange
+        var paymentMethod = new PaymentMethod(new TokenizedPaymentMethod
+        {
+            Type = type,
+            Token = "test-token"
+        });
+        var options = new JsonSerializerOptions { Converters = { new PaymentMethodJsonConverter() } };
+
+        // Act
+        var json = JsonSerializer.Serialize(paymentMethod, options);
+
+        // Assert
+        Assert.Contains($"\"type\":\"{expectedTypeString}\"", json);
+        Assert.Contains("\"token\":\"test-token\"", json);
+    }
+
+    // Non-tokenized payment method serialization
+    [Theory]
+    [InlineData(NonTokenizablePaymentMethodType.AccountCredit, "accountcredit")]
+    public void Write_ShouldSerializeNonTokenizedPaymentMethods(NonTokenizablePaymentMethodType type, string expectedTypeString)
+    {
+        // Arrange
+        var paymentMethod = new PaymentMethod(new NonTokenizedPaymentMethod { Type = type });
+        var options = new JsonSerializerOptions { Converters = { new PaymentMethodJsonConverter() } };
+
+        // Act
+        var json = JsonSerializer.Serialize(paymentMethod, options);
+
+        // Assert
+        Assert.Contains($"\"type\":\"{expectedTypeString}\"", json);
+        Assert.DoesNotContain("token", json);
+    }
+}

test/Core.Test/Billing/Premium/Commands/CreatePremiumCloudHostedSubscriptionCommandTests.cs

@@ -1,4 +1,5 @@
-using Bit.Core.Billing.Caches;
+using Bit.Core.Billing;
+using Bit.Core.Billing.Caches;
 using Bit.Core.Billing.Constants;
 using Bit.Core.Billing.Extensions;
 using Bit.Core.Billing.Payment.Models;
@@ -567,4 +568,79 @@ public class CreatePremiumCloudHostedSubscriptionCommandTests
         var unhandled = result.AsT3;
         Assert.Equal("Something went wrong with your request. Please contact support for assistance.", unhandled.Response);
     }
+
+    [Theory, BitAutoData]
+    public async Task Run_AccountCredit_WithExistingCustomer_Success(
+        User user,
+        NonTokenizedPaymentMethod paymentMethod,
+        BillingAddress billingAddress)
+    {
+        // Arrange
+        user.Premium = false;
+        user.GatewayCustomerId = "existing_customer_123";
+        paymentMethod.Type = NonTokenizablePaymentMethodType.AccountCredit;
+        billingAddress.Country = "US";
+        billingAddress.PostalCode = "12345";
+
+        var mockCustomer = Substitute.For<StripeCustomer>();
+        mockCustomer.Id = "existing_customer_123";
+        mockCustomer.Address = new Address { Country = "US", PostalCode = "12345" };
+        mockCustomer.Metadata = new Dictionary<string, string>();
+
+        var mockSubscription = Substitute.For<StripeSubscription>();
+        mockSubscription.Id = "sub_123";
+        mockSubscription.Status = "active";
+        mockSubscription.Items = new StripeList<SubscriptionItem>
+        {
+            Data =
+            [
+                new SubscriptionItem
+                {
+                    CurrentPeriodEnd = DateTime.UtcNow.AddDays(30)
+                }
+            ]
+        };
+
+        var mockInvoice = Substitute.For<Invoice>();
+
+        _subscriberService.GetCustomerOrThrow(Arg.Any<User>(), Arg.Any<CustomerGetOptions>()).Returns(mockCustomer);
+        _stripeAdapter.SubscriptionCreateAsync(Arg.Any<SubscriptionCreateOptions>()).Returns(mockSubscription);
+        _stripeAdapter.InvoiceUpdateAsync(Arg.Any<string>(), Arg.Any<InvoiceUpdateOptions>()).Returns(mockInvoice);
+
+        // Act
+        var result = await _command.Run(user, paymentMethod, billingAddress, 0);
+
+        // Assert
+        Assert.True(result.IsT0);
+        await _subscriberService.Received(1).GetCustomerOrThrow(Arg.Any<User>(), Arg.Any<CustomerGetOptions>());
+        await _stripeAdapter.DidNotReceive().CustomerCreateAsync(Arg.Any<CustomerCreateOptions>());
+        Assert.True(user.Premium);
+        Assert.Equal(mockSubscription.GetCurrentPeriodEnd(), user.PremiumExpirationDate);
+    }
+
+    [Theory, BitAutoData]
+    public async Task Run_NonTokenizedPaymentWithoutExistingCustomer_ThrowsBillingException(
+        User user,
+        NonTokenizedPaymentMethod paymentMethod,
+        BillingAddress billingAddress)
+    {
+        // Arrange
+        user.Premium = false;
+        // No existing gateway customer ID
+        user.GatewayCustomerId = null;
+        paymentMethod.Type = NonTokenizablePaymentMethodType.AccountCredit;
+        billingAddress.Country = "US";
+        billingAddress.PostalCode = "12345";
+
+        // Act
+        var result = await _command.Run(user, paymentMethod, billingAddress, 0);
+
+        //Assert
+        Assert.True(result.IsT3); // Assuming T3 is the Unhandled result
+        Assert.IsType<BillingException>(result.AsT3.Exception);
+        // Verify no customer was created or subscription attempted
+        await _stripeAdapter.DidNotReceive().CustomerCreateAsync(Arg.Any<CustomerCreateOptions>());
+        await _stripeAdapter.DidNotReceive().SubscriptionCreateAsync(Arg.Any<SubscriptionCreateOptions>());
+        await _userService.DidNotReceive().SaveUserAsync(Arg.Any<User>());
+    }
 }