As it’s stated in the terms & conditions that editing of order is not allowed after checking out, the outlet should inform customers that it’s not possible to edit / change orders. We do not provide payment refunds for customer mistakes. 

In case if we really need to do a refund, it would be on a case by case basis, upon receiving merchant management approval. 

Under normal circumstances, we would recommend a voucher refund so we could keep the customer would return and to ease Finance’s billing purposes.