Unhelpful business

Never take a phone contract out with MTN if you are unhappy and return the device they continue to bill you even after a letter stating the acc was cancelled. I went in store for over 6 months to try and resolve this issue with no help as now after 3 years I am being called by debit collectors (vericred) who won't even speak to me or answer emails, much like mtn. This is ridiculous and I will never recommend mtn to any living person. You people are unhelpful, Columbine MTN store is where this all took place! Do not I repeat ever take a contract out with mtn