diff --git a/app/api/services/base_service.py b/app/api/services/base_service.py
index d30619b..53bcfe9 100644
--- a/app/api/services/base_service.py
+++ b/app/api/services/base_service.py
@@ -123,6 +123,7 @@ class BaseService:
 
         return {
             "interest": interest,
+            "interest_amount": interest_amount,
             "management": management,
             "insurance": insurance,
             "vat": vat,
diff --git a/app/api/services/select_offer.py b/app/api/services/select_offer.py
index a039149..d2fed69 100644
--- a/app/api/services/select_offer.py
+++ b/app/api/services/select_offer.py
@@ -63,6 +63,7 @@ class SelectOfferService(BaseService):
                 insurance = charges["insurance"]
                 vat = charges["vat"]
                 repayment_amount = charges["repayment_amount"]
+                interest_amount = charges["interest_amount"]
 
 
                 # Calculate the repayment dates
@@ -81,11 +82,12 @@ class SelectOfferService(BaseService):
 
                 offers = [
                     {
-                        "offerId": offer.id,
+                        "offerId": offer.offer_id,
                         "productId": product_id,
                         "amount": amount,
                         "upfrontPayment": upfront_payment,
                         "interestRate": offer.interest_rate,
+                        "interestAmount": interest_amount,
                         "managementRate": offer.management_rate,
                         "managementFee": management["fee"],
                         "insuranceRate": offer.insurance_rate,