Game not able to provide proof of purchase

In December 2014 I purchased a Sinoteq HD projector from Game in Lephalale. Unfortunately I lost the proof of purchase when I cleaned house. Well in late April the projector blew its power supply and I was forced to take it back to Game. At the store they asked for my proof of purchase which I could not provide and I explained to them why. I then showed them my bank statement with proof of Game purchase on and they said it will not suffice. I asked them to show me my proof of purchase record and copy they have in store and they also couldn't show me the documentation. Now if you read the Ethics statement on their Game website they state in point 3 that 'our records of business transactions will be accurate and reliable'. Thats not true cause my records of purchase are lost and they made me pay R699.00 to fix the projector, ignoring the 1 year warranty guarantee I have on it. I feel I have been cheated into paying for something thats under warranty and that Game management has failed to deliver on quality customer service.