MTN KEEP DEBITING MY ACCOUNT - DONT HAVE AN ACCOUNT

I am totally at my wits end with MTN. Do not have an account, never had one but MTN keeps debiting my account. Went into MTN in Menly beginning of Sept and the staff were totaly unhelpful. I had to find out for myself to contact MNT *****. I filled in a ***** form and got a Ref: # ********** 9. I have responded on numerous occassions to the mail I got ( one and only supplying Ref number). Low and behold MTN has gone and debited my account again this month. Even though I reverse the debit I am being charged R151.00 for the returned debit and R18.00 for a monthly debit order fee . IS THIS FAIR.....NOOOOOOOOOO If I do not have a response from MTN within 5 days I am taking this matter to the Ombudsman ( who by the way is extremely helpful ).