diff --git a/app/api/schemas/repayment.py b/app/api/schemas/repayment.py
index 90e1b61..b0d4df1 100644
--- a/app/api/schemas/repayment.py
+++ b/app/api/schemas/repayment.py
@@ -5,9 +5,8 @@ class RepaymentSchema(Schema):
     type = fields.Str(required=False)
     msisdn = fields.Str(required=False) #optional
     debtId = fields.Str(required=True)
-    productId = fields.Str(required=True)
     transactionId = fields.Str(required=True)
     accountId = fields.Str(required=True)
     customerId = fields.Str(required=True)
-    channel = fields.Str(required=True)
+    loanRef = fields.Str(required=True)
     initiatedBy = fields.Str(required=False)
diff --git a/app/api/services/repayment.py b/app/api/services/repayment.py
index c580b60..4aef0f8 100644
--- a/app/api/services/repayment.py
+++ b/app/api/services/repayment.py
@@ -32,20 +32,22 @@ class RepaymentService(BaseService):
                 customer_id =  validated_data.get('customerId')
                 request_id =  validated_data.get('requestId')
                 loan_id = validated_data.get('debtId')
-                product_id = validated_data.get('productId')
                 account_id = validated_data.get('accountId')
-                customer = Customer.get_customer_with_loan_list(customer_id)
+                loan_ref = validated_data.get('loanRef')
+                # customer = Customer.get_customer_with_loan_list(customer_id)
                 transaction_id  = validated_data.get('transactionId')
                 initiated_by = validated_data.get('initiatedBy')
         
                 if(RepaymentService.validate_account_ownership(account_id = account_id, customer_id = customer_id)):
 
+                    # Check loan exists
+                    loan = Loan.get_customer_loan(loan_id = loan_id, customer_id = customer_id)
+
                     # Save the repayment details  
                     repayment = Repayment.create_repayment(
                         customer_id = customer_id,
-                        loan_id = loan_id,
-                        product_id = product_id,
-                        transaction_id=transaction_id
+                        loan = loan,
+                        transaction_id = transaction_id
                     )
 
                     if not repayment:
@@ -66,7 +68,8 @@ class RepaymentService(BaseService):
                 response_data = {
                     "transactionId": transaction_id,
                     "customerId": customer_id,
-                    "productId": product_id,
+                    "productId": loan.product_id,
+                    "loanRef": loan_ref,
                     "debtId": loan_id
                 }
 
diff --git a/app/api/services/select_offer.py b/app/api/services/select_offer.py
index dc8f912..c73be44 100644
--- a/app/api/services/select_offer.py
+++ b/app/api/services/select_offer.py
@@ -59,8 +59,11 @@ class SelectOfferService(BaseService):
 
                 db.session.flush()
 
-                if(amount < offer.min_amount):
+                if amount < offer.min_amount:
                     return ResponseHelper.error(result_description="The amount is less than the minimum allowed offer amount.")
+                elif amount > offer.max_amount:
+                    return ResponseHelper.error(result_description="The amount is greater than the maximum allowed offer amount.")
+
                     
 
                 charges = SelectOfferService.calculate_charges(offer, amount)
diff --git a/app/models/customer.py b/app/models/customer.py
index 882dd34..883d34f 100644
--- a/app/models/customer.py
+++ b/app/models/customer.py
@@ -48,6 +48,8 @@ class Customer(db.Model):
     def create_customer(cls, id, msisdn, country_code, account_id, account_type='savings'):
         if cls.query.filter_by(id=id).first():
             raise ValueError("Customer already exists")
+        elif Account.query.filter_by(id=account_id).first():
+            raise ValueError("Account already exists")
         
         # Create the customer
         customer = cls(
diff --git a/app/models/repayment.py b/app/models/repayment.py
index 590db56..be77d2c 100644
--- a/app/models/repayment.py
+++ b/app/models/repayment.py
@@ -23,15 +23,7 @@ class Repayment(db.Model):
     transaction_id = db.Column(db.String(50), nullable=True)
 
     @classmethod
-    def create_repayment(cls, customer_id, loan_id, product_id, transaction_id):
-
-
-        # Check customer exists
-        if not Customer.is_valid_customer(customer_id):
-            raise ValueError("Invalid customer")
-
-        # Check loan exists
-        loan = Loan.get_customer_loan(loan_id = loan_id, customer_id = customer_id)
+    def create_repayment(cls, customer_id, loan, transaction_id):
         
         # Check that the loan is active
         if loan.status not in [LoanStatus.ACTIVE, LoanStatus.START_REPAY]:
@@ -40,8 +32,8 @@ class Repayment(db.Model):
 
         repayment = cls(
             customer_id=customer_id,
-            loan_id=loan_id,
-            product_id=product_id,
+            loan_id=loan.id,
+            product_id=loan.product_id,
             transaction_id = transaction_id,
             created_at=datetime.now(timezone.utc),
             updated_at=datetime.now(timezone.utc)
diff --git a/app/swagger/schemas/RepaymentRequest.json b/app/swagger/schemas/RepaymentRequest.json
index 9543f74..1c28b71 100644
--- a/app/swagger/schemas/RepaymentRequest.json
+++ b/app/swagger/schemas/RepaymentRequest.json
@@ -9,10 +9,6 @@
             "type": "string",
             "example": "10"
         },
-        "productId": {
-            "type": "string",
-            "example": "101"
-        },
         "transactionId": {
             "type": "string",
             "example": "20171209232115"
@@ -21,9 +17,9 @@
             "type": "string",
             "example": "CID0000025585"
         },
-        "channel": {
+        "loanRef": {
             "type": "string",
-            "example": "USSD"
+            "example": "Trx5847365252USSD3MPC"
         },
         "accountId": {
             "type": "string",