In Breach of Contract

I am very disgusted with Vodacom. I want to get out of this contract, because THEY are in breach of contract. In our area we are battling with signal. The contract states that they will deliver a service, like network coverage and I pay them a monthly fee. I complained about the poor network coverage 6 years ago, and I received messages that they are working on the problem. Well, it is getting worse by the day!!!! I complained again and first they just closed the case, when I complained, they said they can't get hold of me, well it is 50/50, my complaint is about poor signal so they will not get hold of me, and the other 50 is that actually one of their people did phone me and he said that he will send me a sms to which I have to respond with my GPS coordinates, guess what? I am still waiting. I want to migrate to MTN, because they deliver. Vodacom is busy *****ing my money and they couldn't care less!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!