MTN disgrace to our society

MTN online services, I cancelled my contract upon receipt of the "wrong product" delivered, It seems you are sent from department to department and eventually they blame the delivery/dispatch department, but nobody give you the correct department of official to deal with your dispute. I cancelled and followed up numerous times from date 24 February 2022 and they simply refuse to cancel the RETURNED device, which was returned by their own dispatch company, the same that delivered. There is simply not communication between their departments and nobody even bother to finalise the cancellation. They keep deducting by debit order, and I just received an sms that they want now to deduct the entire contract amount at once. THIS IS THEFT!!!!!!!! refusing to cancel the contract, after the deal was cancelled telephonically on the 26th, and there is no cancellation letter whatsoever.