Contract Cancellation - No Help!!!

I have been trying to cancel a contract with MTN for a few years now. I have been emailing any email address I could find, with no response from MTN. We have paid the cancellation fees a year ago and still they continue to deduct from our account for an amount we did not agree to. No contract was signed for an upgrade, no notice of an upgrade was sent. I did request the signed contract for the upgrade and that is when I stopped receiving any correspondence from MTN. They even deducted a debit order from another account which I did not even know they had the details of. They are just ridiculous. Please think twice before signing a contract with them