Bad service on contract/phone

i did a upgrade about 2 weeks ago, the first week phone gave me lots of problems. i took the phone back, it was sent in for repairs. came back after 3 weeks went in again for same problem. now they refuse to give me a new phone. I've been without a phone for 2 weeks. and am battling to cancel my contract, no one is giving me straight answers, and i am FED UP!!! i just want my contract cancelled. and i refuse to take the handset back when it does eventually come back from repairs. very very angry. <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br> <br>