diff --git a/app/api/services/base_service.py b/app/api/services/base_service.py
index 53bcfe9..4a6fd86 100644
--- a/app/api/services/base_service.py
+++ b/app/api/services/base_service.py
@@ -48,12 +48,14 @@ class BaseService:
         """
         Create a new transaction.
         """
+        channel = "USSD" if validated_data.get("channel") is None else validated_data.get("channel")
+
         return Transaction.create_transaction(
             transaction_id = validated_data.get("transactionId"),
             customer_id =  validated_data.get('customerId', None),
             account_id = validated_data.get("accountId", None),  
             type = cls.TRANSACTION_TYPE,
-            channel = validated_data.get("channel"),
+            channel = channel,
         )
     
     @classmethod