Telkom is the worse service provider

I am actually very irrate at this time.. Telkom has been debiting my cheque account none stop for moneys that they owe me.. I'm frustrated and angry at the fact that when you take out a phone contract or an upgrade u get charged for services that you did not sign up for and what's worse is that you are being charged for it.. I need help urgently.. I can't handle this situation anymore.. No one at the store wants to help.. How do u pay for something you did not use and sign up for???