At the end of July.2017 ,one customer from indonesia placed an order of a special magnet system,  total amount USD4300.Everything went smoothly and we delivered magnet as scheduled.Customer arranged the payment before shipment  while we found the totol amount we received is USD4945. We informed the customer  about this mistake and told them  we will definitly return the money overpaid ASAP.In the following days,we dealt with the return  actively and  learnt from our bank that the simplest way  to return the money  is  in the name of commission.Therefore，we issued a commssion aggrement  and asked customer to make an invoice of commssion.At last, we returned the money as per the arrangement and invoice at the beignning of Nov.2017 successfully.