Telkom keeps taking money from me ********ly!

I had a contract with Telkom years ago, the contract ended but they kept taking money from me every month. I have cancelled this and taken it up with Telkom more times than I can remember. My account keeps getting debited. when I cancel or reverse the amount, I'm debited twice the amount the following month. This has been going on for years and years. I need Telkom to please stop taking money from my account and please pay me back for all the years that they have been taking money from my account.