Debiting my account without my permission

I have been battling with Vodacom for over a year. They continuously charge me for all sorts of ******* I did not subscribe for. Almost every month I use the USSD process to unsubscribe from everything. Doesn't seem to have any impact. I have a list of messages, mails and phone calls to them. Customers are not allowed to speak to anyone with any knowledge or authority. In my last written communication with Vodacom I stated that they did not have my permission to subscribe me or charge me for ANYTHING without my express written instruction or recorded telephone conversation. They have now charged me for a Showmax subscription. I'm in the process of lodging a complaint with the ombudsman and financial services board as my account is being debited without my permission. What do I need to do?! Vodacom staff refuse to give me any information regarding dates and times I supposedly subscribed to services.