Vodacom *****ing my money and i have no contract

I have cancelled my contracts with vodacom years ago but still they feel the need to debit my account.I do not have a sim card or a mobile from them.I have frequented The Glen Southdate and Sandton but no assistance .I have called on numerous occasions still nothing.They steel my money on a monthly basis.everytime i go to the outlets then i am told to call the call centre and vise versa.They refuse to give me the details of the Ombud.i am really angry and dont know how to stop the debts.