Debit Order after i have cancelled Contract

I have been Mtn customer for almost 15 years using same no It's too disappointing to see how you treat me as a customer my loyalty meant nothing to you <br> I have made a complained regarding a contract that was not cancelled after numerous requests made that I do not need another contract instead you have topped up my account and I was promised that these matter will be resolved instead you took back your Airtime but debited my account after I have cancelled many times now I am paying for something that I do not have and do not want what's next you going to list me on credit bureau that I owe because I am going to reverse the debited money <br> As I did not authorize it Pathetic <br> I'm in my worst disgust because of the incompetence of MTN <br>