MTN ROBBING PEOPLE *******LY

Well MTN are at it again.....I opened my latest cell account and noticed once again they have added on a fee for rejected debit order......I do not have a debit order for them, I can prove 1000% that there have not been any unpaid debit orders on my bank statement.....i HAD CANCELLED MY PREVIOUS DEBIT ORDER A FEW YEARS AGO IN STORE.......I have had message from them advising me that I was on cash basis.......please MTN train your people......this is getting ridiculous now.....I am not able to go into the branch each and every month to sort out your problem......