Charged for a canceled contract

I've been trying to cancel my mtn contract since June 2023 as it has come to an end with no success,I called ,sent an email charged more that what my initial premium because they have put my account on month to month without my knowledge, then I asked them to remove it from month to month which I don't think it was cause I was charged again end of July and they took their data back but with no refund. I tried getting hold of them got cut off,asked to speak to the manager but it never happed I'm still not sure if my contract is been cancelled to this date or not,mtn is a **** with bad service to their customers.