At payment processing system, in some circumstances merchant will have to refund twice for one transaction. The first time merchant submit a partial refund request. But later due to customer end issues, the refund needed another refund for remaining balance. It is probably due to product cannot be satisfied by customer or dispute, complaint. Generally the second refund request cannot be directly processed through the system automatically. In such cases the merchant should contact the service provider to manually refund. If they confirm a second partial refund can be done. They will record this refund under merchant statement and deduct from the settlement although the system cannot show this. But if the refund request is issued for transaction dated long ago such as 6 months over. The refund request probably will be failed.
Another question concerned is the refund amount. As the cross border transaction involves currency conversion, the merchant may worry that if the refund amount exactly the amount charged on customer end. Despite the currency conversion occurred in the processing of transaction, the refund amount will be processed through the bank with exactly the same amount of the transaction. Merchant can rest assure of this point. For refund procedure, it normally takes 2-4 weeks or even longer depends on the bank system processing time. As there are two banks involved plus credit card association within the bank system. The merchant is advised to explain this to customer. The customer can also contact their bank in advance to speed up the procedure.