Phone sent in and returned in bad condition.

Hi, I bought a phone from vodacom via CNA on 26/07/2015. After 2 weeks the phone's flash stopped working. I went to vodacom in Moffett on Main Shopping Centre in PE. The phone still looked like new( technically it is) when I took it in on the 08/08/2015. Now almost 2 weeks later, I get contacted and told to collect my phone. Firstly, they did not even clean the phone it was covered in dirty fingerprints. The phone is a waterproof phone and does not have a back cover that you can open to remove a battery etc, but when I took a closer look it looked like they forced the thing open with a *****driver( marks on the back indicate as much) and now the back is not closing properly its loose and the plastic underneath it is pealing out the sides, because of this the phone's waterproof capabilities are gone. I told them to keeps the phone and I'm waiting for a call from the manager on Monday. I'm not even interested in the phone anymore neither do I want a new one because the flash problem is a common one, its going to happen again. I just want my money back! I bought the phone on prepaid, I'm only 18 and I saved a long time to buy the phone!Manager was not on the premises. I'm very unhappy