MTN contract cancellation from hell

I had 2 contracts with MTN. I know canceling a contract is an issues hence the reason I started phoning in July 2021 to make sure I cancel both contracts in time. The date originally given by the operator for the one contract was wrong and now Im being charged for her mistake. I was n faithful MTN customer, paying my bills for 24months and now this is the service I receive? Today a massive amount was deducted from my account (4 Jan 2022) and this is starting to cost me money. Mtn just doesn’t care. I have requested that they listen to all the recordings and gave references of most of the calls and still this is going on. MTN when is this goung to stop?