Contract Cancellation

It has been over 4 months trying to cancel my contract with MTN. I called them in November 2020 to cancel and only noticed on 15 January when my line was suspended that my contract is still active. I called them again and I was told that they will fix my issue in two working days. And today 16 February 2021 i got a message telling me my contract is still active and I owe some money.. Very bad service