Mtn ripping people off and their incompetence

I had a contract with Mtn and it has end in January 2022. I go debited in February and I was told they moved me to a month to month and I never signed up for that and I still ask for a contract when I signed for that, because I don't want to extend my contract. The lady I spoke to the said she'll put me on zero rated plan or something so I don't have to pay anything. 1 of March I get debited again and then I was told the lady that was suppose to cancel my contract did not complete the process 🙄 and it will be investigation. Few days later I decided to reverse the debit order since no one is getting back to me. I then received a threatening sms saying I will not be able make phone calls since I owe them. I then called I was told somebody will call me from the cancelation department so my service won't be suspended, immediately after I put the phone down I get an sms saying I agreed to settle the premium which was total bull because I never said that. I then called for cancelation department and they don't work on a holiday and I must call again. I'm so fed up and Gatvol with Mtn and apparently they were told in December that contracts that are expired they must automatically put on a month to month but I don't remember receiving such communicating from Mtn which to me is total bull**** because now you wanna ripping us off.