Poor service

In July I went to Northgate mall mtn to go and cancel my contract, and I was told to call around 11 August which I did then my number was on prepaid, the i was told to pay 429,i asked them how cause the August statement was 209,which ibwas paying every month and i have never skipped a single payment, i sent them all the proof of payment and their statement and I was taken from pillar to post, inwas told its a fee cause I did early cancelation, i told them I didn't do early cancelations cause I went to mtn store and I was told the contract is ending in August so i must call around the 9- 11august, since today i have never had a valid answer, one month my number was deactivated and when I call to ask why they said its mtn fault cause there was a month where mtn overcharged clients and i was one of them and they opened their my line, i have been using mtn contract for over 10 years and I have never skipped a payment si now cause I can't afford contract phone anymore cause of this pandemic they want to rob me. Every time i open a case after few day or a month later I will get an sms saying it has been closed without informing me what is the outcome of my query.. Please i need answers cause I don't want to see my name on ITC cause on Mtn.. My number is ***