No Signal, Won't Cancel Contract

I was a Vodacom customer for over twenty years. I moved into an area where the Vodacom signal was non-existent. I do not have a land-line, and rely on my phone for work - which i do from home. I spoke to numerous people at Vodacom, and eventually the Technical department conceded that there was a signal problem in my area, and that installing a booster in my house would not help. They said they would be dealing with the problem only in about a years time. As Vodacom was now in breach of our contract, I requested that my contract be cancelled. After about twenty phone calls, and being pushed from pillar to post, i abandoned my contract (as is my right given their breach). They are still taking money out of my account and threatening to hand me over. Just another example of how eager they are when you sign up, but completely disappear when they don't live up to their obligations.