Telkom deducting monthly money for a disconnected account

I need help from anyone who can see this review please! Telkom I have been suffering a R200 charge monthly since February for a month to month contract that they cancelled in January. No data and no connection received since then but they are still charging me every month and will continue doing so forever. I need urgent help from anyone who knows how to challenge a creditor who is charging you unjustly please.