MTN worst possible customer service ever

Mtn is the worst service provider ever, their customer service department are of no assistance at all. I have a wifi contract in place that states an amount of R399 will be taken off each month as a debit order however mtn has decided to subscribe me to services that I did not subscribe to as it is a wifi router only contract. Now they want to charge me a complete cancelation of my contract even though I am not at fault and they are in breach of the contract.