Cancel MTN

I have a data contract with MTN which i have been trying to cancel for 4 months now. The contract is 'out of contract' so this should not be too difficult! I cannot cancel at a MTN store because this is apparently not allowed. I called in November 2023, Ref 1-***, then again on the 16th January 2024, Ref 1-***1. This month again the money gets deducted. Can somebody who actually knows how to cancel a contract please call me from MTN?