Faulty phone and Breach of Contract

I have upgraded my phone contract with MTN in East Gate Mall and two months later my IPHONE 6plus had a problem and started to freeze. I returned the phone to the West Gate MTN for repairs I was then told that the phone does not exist and its not on their records which really puzzled me because I just could not understand what they mean its not on their system. I am sitting with a phone that no one seems to know about it and I have even requested that they check at their depot. I have gotten such bad treatment and no one seems to be able to assist me with a phone that they gave me. At one point I was told that they can see the upgrade but they can't find the contract. The sad part money is been taken from my account which means I am paying for something I don't have. When I speak to them they tell me that its my responsibility to check the IMEI number on the phone and its not their fault that this has happened. I really would like to have my phone back in working order or have this contract cancelled because I have not seen such a thing from such a big establishment. Their staff that I have spoken to are so *********** and quick to point fingers the other direction. <br> <br> Kind Regards