********** and *********** customer service

I requested a cancellation in April and to this day Telkom is still charging me for a contract that has been cancelled. Every month they attempt to debit and wen I go to my bank to reverse the debit order, the charge me another R202 for cancelling the debit. I have been speaking to their agents about this since June and they keep saying that they will get their supervisor to call me but I have never received one call from them. Now they are threatening to have me blacklisted for a contract that has been cancelled but they still charging me for it regardless.