TAKE MY NEW PHONE AND GIVE ME AN OLD ONE.

I have had a Cell C contract for the past 6 months. Exactly 11 days ago my handset stopped working and I took it back to the store. It went into repairs and I was informed that it is a blackberry software problem and that the phone could not be repaired. I was advised that I would be receiving a \NEW DEVICE"which the software has been loaded on. Today I went to collect the phone but it was not what I was expecting. Having had my phone for almost 6 months"