VODACOM BREACH CONTRACT, THREATENS WITH BLACKLIST

I took a contract about two years ago, at three rivers,blackberry Q5, the phone was faulty and after 2 weeks i recieved a new phone. It was faulty AGAIN! After i wasted allot of time and petrol they gave me a list of phones i can choose from but it was cheaper phones and i still needed to pay the same amount contract. They said its maybe the simcard and i baught a new simcard aswell 1Gig data to see if the phone is fine. It was still faulty so vadacom vanderbijilpark repairs took the phone with simcard and assesories. I called cancelations department and i have emails vodacom wich i have proof of. They said they will cancel the contract and refund me on the money about the simcard and the data i lost. I emailed them again. I did not hear anything so i left it. Now they call me and say if i dont pay about R3000 they are handing me over i can get blacklisted. I went again to the vodacom shop in three rivers where the contract was taken out and again they say they cant help me. They checked the number and its already given to a other person. POOR SERVICE IN STORES AND CALL CENTER! CANCELATION DEPARTMENT. I dont know what to do or where to go!! WHAT TYPE OF SERVICE PROVIDER IS VODACOM!