diff --git a/Streetwriters.Common/Models/GetCustomerResponse.cs b/Streetwriters.Common/Models/GetCustomerResponse.cs
new file mode 100644
index 0000000..59203e4
--- /dev/null
+++ b/Streetwriters.Common/Models/GetCustomerResponse.cs
@@ -0,0 +1,21 @@
+namespace Streetwriters.Common.Models
+{
+    using System;
+    using System.Collections.Generic;
+
+    using System.Text.Json;
+    using System.Text.Json.Serialization;
+    using System.Globalization;
+
+    public partial class GetCustomerResponse : PaddleResponse
+    {
+        [JsonPropertyName("data")]
+        public PaddleCustomer Customer { get; set; }
+    }
+
+    public class PaddleCustomer
+    {
+        [JsonPropertyName("email")]
+        public string Email { get; set; }
+    }
+}
diff --git a/Streetwriters.Common/Models/GetSubscriptionResponse.cs b/Streetwriters.Common/Models/GetSubscriptionResponse.cs
index c718e1e..c431915 100644
--- a/Streetwriters.Common/Models/GetSubscriptionResponse.cs
+++ b/Streetwriters.Common/Models/GetSubscriptionResponse.cs
@@ -7,13 +7,10 @@ namespace Streetwriters.Common.Models
     using System.Text.Json.Serialization;
     using System.Globalization;
 
-    public partial class GetSubscriptionResponse
+    public partial class GetSubscriptionResponse : PaddleResponse
     {
         [JsonPropertyName("data")]
         public Data Data { get; set; }
-
-        [JsonPropertyName("meta")]
-        public Meta Meta { get; set; }
     }
 
     public partial class Data
@@ -214,10 +211,4 @@ namespace Streetwriters.Common.Models
         [JsonPropertyName("cancel")]
         public Uri Cancel { get; set; }
     }
-
-    public partial class Meta
-    {
-        [JsonPropertyName("request_id")]
-        public string RequestId { get; set; }
-    }
 }
diff --git a/Streetwriters.Common/Models/GetTransactionInvoiceResponse.cs b/Streetwriters.Common/Models/GetTransactionInvoiceResponse.cs
index c745319..9edd9d4 100644
--- a/Streetwriters.Common/Models/GetTransactionInvoiceResponse.cs
+++ b/Streetwriters.Common/Models/GetTransactionInvoiceResponse.cs
@@ -7,18 +7,14 @@ namespace Streetwriters.Common.Models
     using System.Text.Json.Serialization;
     using System.Globalization;
 
-    public partial class GetTransactionInvoiceResponse
+    public class GetTransactionInvoiceResponse : PaddleResponse
     {
         [JsonPropertyName("data")]
         public Invoice Invoice { get; set; }
-
-        [JsonPropertyName("meta")]
-        public Meta Meta { get; set; }
     }
 
     public partial class Invoice
     {
-
         [JsonPropertyName("url")]
         public string Url { get; set; }
     }
diff --git a/Streetwriters.Common/Models/GetTransactionResponse.cs b/Streetwriters.Common/Models/GetTransactionResponse.cs
index c293dcf..5ef8102 100644
--- a/Streetwriters.Common/Models/GetTransactionResponse.cs
+++ b/Streetwriters.Common/Models/GetTransactionResponse.cs
@@ -7,12 +7,9 @@ namespace Streetwriters.Common.Models
     using System.Text.Json.Serialization;
     using System.Globalization;
 
-    public partial class GetTransactionResponse
+    public partial class GetTransactionResponse : PaddleResponse
     {
         [JsonPropertyName("data")]
         public TransactionV2 Transaction { get; set; }
-
-        [JsonPropertyName("meta")]
-        public Meta Meta { get; set; }
     }
 }
diff --git a/Streetwriters.Common/Models/ListTransactionsResponseV2.cs b/Streetwriters.Common/Models/ListTransactionsResponseV2.cs
index f0da768..647ccd0 100644
--- a/Streetwriters.Common/Models/ListTransactionsResponseV2.cs
+++ b/Streetwriters.Common/Models/ListTransactionsResponseV2.cs
@@ -7,13 +7,10 @@ namespace Streetwriters.Common.Models
     using System.Text.Json.Serialization;
     using System.Globalization;
 
-    public partial class ListTransactionsResponseV2
+    public partial class ListTransactionsResponseV2 : PaddleResponse
     {
         [JsonPropertyName("data")]
         public TransactionV2[] Transactions { get; set; }
-
-        [JsonPropertyName("meta")]
-        public Meta Meta { get; set; }
     }
 
     public partial class TransactionV2
@@ -497,12 +494,6 @@ namespace Streetwriters.Common.Models
     //     public string CardholderName { get; set; }
     // }
 
-    public partial class Meta
-    {
-        [JsonPropertyName("pagination")]
-        public Pagination Pagination { get; set; }
-    }
-
     public partial class Pagination
     {
         [JsonPropertyName("per_page")]
diff --git a/Streetwriters.Common/Models/PaddleResponse.cs b/Streetwriters.Common/Models/PaddleResponse.cs
new file mode 100644
index 0000000..5ccb625
--- /dev/null
+++ b/Streetwriters.Common/Models/PaddleResponse.cs
@@ -0,0 +1,24 @@
+namespace Streetwriters.Common.Models
+{
+    using System;
+    using System.Collections.Generic;
+
+    using System.Text.Json;
+    using System.Text.Json.Serialization;
+    using System.Globalization;
+
+    public partial class PaddleResponse
+    {
+        [JsonPropertyName("error")]
+        public PaddleError Error { get; set; }
+    }
+
+    public class PaddleError
+    {
+        public string? Type { get; set; }
+        public string? Code { get; set; }
+        public string? Detail { get; set; }
+        [JsonPropertyName("documentation_url")]
+        public string? DocumentationUrl { get; set; }
+    }
+}
\ No newline at end of file
diff --git a/Streetwriters.Common/Models/SubscriptionPreviewResponse.cs b/Streetwriters.Common/Models/SubscriptionPreviewResponse.cs
index 444d82d..7d57c99 100644
--- a/Streetwriters.Common/Models/SubscriptionPreviewResponse.cs
+++ b/Streetwriters.Common/Models/SubscriptionPreviewResponse.cs
@@ -7,13 +7,10 @@ namespace Streetwriters.Common.Models
     using System.Text.Json.Serialization;
     using System.Globalization;
 
-    public partial class SubscriptionPreviewResponse
+    public partial class SubscriptionPreviewResponse : PaddleResponse
     {
         [JsonPropertyName("data")]
         public SubscriptionPreviewData Data { get; set; }
-
-        [JsonPropertyName("meta")]
-        public Meta Meta { get; set; }
     }
 
     public partial class SubscriptionPreviewData
diff --git a/Streetwriters.Common/Services/PaddleBillingService.cs b/Streetwriters.Common/Services/PaddleBillingService.cs
index 06e559e..a536359 100644
--- a/Streetwriters.Common/Services/PaddleBillingService.cs
+++ b/Streetwriters.Common/Services/PaddleBillingService.cs
@@ -80,26 +80,26 @@ namespace Streetwriters.Common.Services
             return response.IsSuccessStatusCode;
         }
 
-        public async Task<SubscriptionPreviewResponse?> PreviewSubscriptionChangeAsync(string subscriptionId, string newProductId)
+        public async Task<SubscriptionPreviewResponse?> PreviewSubscriptionChangeAsync(string subscriptionId, string newProductId, bool isTrialing)
         {
             var url = $"{PADDLE_BASE_URI}/subscriptions/{subscriptionId}/preview";
             var response = await httpClient.PatchAsync(url, JsonContent.Create(new
             {
-                proration_billing_mode = "prorated_immediately",
+                proration_billing_mode = isTrialing ? "do_not_bill" : "prorated_immediately",
                 items = new[] { new { price_id = newProductId, quantity = 1 } }
             }));
             return await response.Content.ReadFromJsonAsync<SubscriptionPreviewResponse>();
         }
 
-        public async Task<bool> ChangeSubscriptionAsync(string subscriptionId, string newProductId)
+        public async Task<PaddleResponse?> ChangeSubscriptionAsync(string subscriptionId, string newProductId, bool isTrialing)
         {
             var url = $"{PADDLE_BASE_URI}/subscriptions/{subscriptionId}";
             var response = await httpClient.PatchAsync(url, JsonContent.Create(new
             {
-                proration_billing_mode = "prorated_immediately",
+                proration_billing_mode = isTrialing ? "do_not_bill" : "prorated_immediately",
                 items = new[] { new { price_id = newProductId, quantity = 1 } }
             }));
-            return response.IsSuccessStatusCode;
+            return await response.Content.ReadFromJsonAsync<PaddleResponse>();
         }
 
         public async Task<bool> CancelSubscriptionAsync(string subscriptionId)
@@ -125,5 +125,14 @@ namespace Streetwriters.Common.Services
             }));
             return response.IsSuccessStatusCode;
         }
+
+        public async Task<GetCustomerResponse?> FindCustomerFromTransactionAsync(string transactionId)
+        {
+            var transaction = await GetTransactionAsync(transactionId);
+            if (transaction == null) return null;
+            var url = $"{PADDLE_BASE_URI}/customers/{transaction.Transaction.CustomerId}";
+            var response = await httpClient.GetFromJsonAsync<GetCustomerResponse>(url);
+            return response;
+        }
     }
 }
\ No newline at end of file