MTN do not give money back

I had overpaid my MTN contract one month. I had phoned in to close my contract in June. I was told that I would only be able to phone in to get the credit refunded once my contract was closed in July. So I waited and requested the refund, dealt with 3 different consults within a week because the previous one would either not take all the information or did not process the request. I was told to wait 21 days, I did, I phoned in again and was told to wait 7 days. Still do not have my money back. Really poor etiquette and service.