Bad call centre service & also no data coverage unable to use mobile date

I am fed up with Cell C, I have been calling & requesting to cancel contract due to never having being able to use my mobile data & also extremely bad & *********** call centre staff. Each time I call the staff either can not speak English or they are totally rude to the point where I just hang up on the call. This is the 3rd time I have to resort to Hello Peter to resolve my problem. All I want to do is cancel my contract with cell c. But no body can assist me.