Samsung TV stopped working

I purchased a Samsung LCD tv for the value of R4999 on the 12th October 2014. The day I purchased it the man had taken it down and I think it was a display model as it was opened it took him another half an hour before he brought it to the tills down stairs and I had waited another 40 minutes before paying as he went up and down as it had no price sticker on it. He was checking on the system for the code.I left and got home assembled it and now a year and 2/3 months later it has simply stopped working even after the man promised there was nothing wrong with it. It was the last one and display showed me it works and ran around. I still have the slip box and tv in good condition nothing has happened to it after leaving the shop.. maybe I should of taken one in a sealed box but now what do I do as no one spends R5000 for a tv only for it to last a year? Tried calling customer service to advise me no luck.