Try cancel MTN contracts - impossible

I have tried to cancel an old account 7 times- going to a store- wast of time they can’t help you. Calling waste of time they say will cancel but never happens, emailing nothing happens. It is actually physically impossible to cancel an account. Every month for years they take off an amount of R209 for nothing - no services no billings no anything and yet still they do not cancel. I have spent so many hours on the phone with them over the years it is rediculous. It seems there is no willingness to cancel when can simply take the money each month and people are too busy to keep checking old accounts. Disgusting