Cancelled Account but line was never cancelled on their side.

Is there a -10 rating? I had a contract with them but cancelled and paid the cancellation fee. They stopped deducting from my account and from Jan 2021 to Nov 2021, they started deducting again but small amounts, it started with 300, went up to 500 so I stopped the debit orders and disputed the money cause I mean I cancelled my account with them. So they handed me over... I called MTN, send the proof of payment and cancellation letter AGAIN, now they are transferring my reference number to different departments everyday and its not being sorted out. This has been going on since Feb 2022. PLEASE HELP!