Disappointed with MTN

To say I'm disappointed is an understatement. Im livid with MTN. I had a contract that came to an end last year in December. I called a month prior (november ) to notify the service provider that I have no intentions of continuing with the contract . The consultant reassured me that the contract was terminated. I had asked for confirmation letter stipulating that indeed the contract has ended and to day I have not received the letter. To cut the long story short I'm still receiving invoices after I terminated the contract and my account is still debited. I have been calling and writing emails to MTN customer support but I have not been assisted. I don't understand why I must continue to pay for a contract that came to an end. Today i received a final notice of of payment for a contract that ended 09th of december 2022.Im definitely taking this matter further.