Upgrade not cancellced

I app**** for a cell phone contract upgrade early February 2015. I then received the cell phone on 10 of February which was delivered to me via courier to my place of work. The package which I received in was very loose and allowed for allot of movement of the device. I then charged the cell phone for 24 hours, after activating the phone I realized that the phone was heating up and freezing. I then on 16th February contacted the call centre and explained to them what is happening with the phone and told them that I was not happy and requested a cancellation on the upgrade. I was given a OBF number OBF 146067 and told that they will get back to me in two working days which there didn't, I have been trying to resolve this matter for the past 6 weeks and I have been pushed to around from department to department..The latest feedback is that they have to check a recording in order to issue a RMA number for the cancellation. I think that the call centre agents in that department are very *********** and I am worried that the fact that they have not done their job I am going to struggle to get the contract cancelled. On top of that I was told that I cannot be transferred to the manager.