Over charged for and expired contract

Hello Peter, I have had a bad relationship with MTN for the past 2 years and the nightmare does not end. I had a contract with mtn which expired 22/08/2022. I called in their call center the previous month July asking what must I do to cancel my contract because of the bad treatment they have given me. I was then advised that I must month end of the day the day my contract ends. When I called their call center again they advised I was supposed to call the previous month of which I advised that I did and the call center agent advised me differently. I was then advised that my contract will be placed on hold for any debit orders until the matter is investigated. Iwas usually debited R329 for my agreed contract. To my surprise I was debited R1200 this month for data that I did not use or agree on. While mtn charges you R200 for a 20gig - 20gig prepaid data. MTN DOES NOT VALUE ITS CLIENTS AND THEY DO NOT SPEAK THE SAME LANGUAGE. IN ALL HONESTY IT I WILL NEVER RECOMMEND MTN TO ANYONE BECAUSE THEY MAKE MONEY BUY ROBBING PEOPLE. NOW THEY WANT ME TO PAY BECAUSE THEY FAIL TO TRAIN THEIR STAFF GOOD CUSTOMER SERVICE? WHY DIDNT THE CANCEL MY CONTRACT WHEN I SAID I WANTED TO CANCEL IT? I HAVE BEEN WAITING FOR MTN TO CONTACT ME EVER SONCE 28/08/2022 not even an email from them till date. Please assist me. My child won't have food because of this.