Sick and tired of MTN

Someone renewed a contract using my details on MTN, i have informed MTN that i did not renew a contract i even went to the police station to make an affidavit. I then got a call from MTN saying that they will stop the deductions and cancel the the contract that was renewed under my name. The now is they still deduct the money and its an inconvenience to me. I even blocked them at the bank but what they did they change the amount from R1600 to R1700 and they change the reference no . hence the debit went through again.