repair of phone

I upgraded during July 2014, from scratch the phone would just switch off unexpectedly. The problem occurred more often, up until the point where I had to take out the battery and put it back in in order to get the phone switched on again. Then, during April 2015, I took the phone to Cell C Menlyn to have the problem sorted out. I do have a 2 year guarantee on the phone. End of April 2015 I was notified that I could collect my phone again. They then told me that my phone was replaced with another phone, It was not a new phone, inside was a sticker saying 'refurbished'. About a week later, I noticed that the phone wouldn't charge. At that stage I broke my ankle, and only managed to get to Cell C again about a month later. They took the phone in again, and on 10 June 2015 I was notified that my phone was ready for collection. On 12 June when I went to collect my phone, I was notified that the phone couldn't be repaired and that it was my problem, there is no guarantee on that phone. What the ????? Cell C gave me the phone about a month ago, and then they just shrug their shoulders? I didn't take the phone, and I am waiting for further response from Cell C.