THE WORSE NETWORK SERVICE PROVIDER EVER

Ever since i renewed my contract with Mtn, I've been going through HELL. First, they debited my account for a 2gigs that i never requested and never received. Now, i haven't been able to make calls since January, and i went into an Mtn store in Howick to enquire and i was told that its a technical problem, they working on it. It's been over 4weeks!!!!! When i called 808, i can't get through. Like really, MTN HAS GOT TO BE THE WORSE ****ING NETWORK EVER. I've now had to use my VODACOM sim card on another phone to load airtime and make calls. I've had it, i can't do this anymore. How do you cancel a contract due to relationship failure. Don't tell me i need to pay what i owe, when i haven't been receiving service for what i signed up for. And yes I'm more willing to give the phone back, if that what must happen. If anyone wants a contract, don't take it with MTN, they are the WORSE NETWORK SERVICE PROVIDERS EVER!!!!