Canceled contract

I canceled my contract last year with MTN via customer care and customer care email. I spoken to MTN customer care numeral times ,I have emailed them several times since last year. I even went to MTN in Rustenburg waterfall Mall. And still no one is canceling my contract. Mtn keep on billing me. They even charged me early cancelation fee which I don't understand because I did ask them to cancel my contract once it's done Dec 2022 and I even gave a month's notice as they ask. And did email everything through numeral times. Spoke to people several times. Sit on the line for hours so they can just transfer my call from one to another the whole time. Meanwhile MTN keep on billing me. When you call them the customer care service people are so rude and don't have any telephone manners. Very disrespectful. This is the worst company that I have ever dealt with.