Retentions Department USELESS!!!!

I have two contracts with MTN, but because I left South Africa in June for good I decided to cancel my SIM ONLY contract and continue with the other. I went through the normal process of getting a settlement quote and so forth, long story short, I paid the settlement and before flying I confirmed with MTN that the amount was received and that the contract is cancelled. Two months down the line, I am still being charged for the contract, NOTHING has been cancelled! I emailed retentions last month and they confirmed again it was cancelled, but again this month I was charged for contract! MTN go on about being the best but their service is absolutely PATHETIC!! You can't do a simple job of cancelling a contract for which you gave a settlement amount and received! ****************! I emailed retentions again and am hoping for a better outcome.