Pathetic service

I bought a 55 inch almost 2 years ago. The TV was mounted into my ceiling. A few weeks ago,the screen just went black and I returned it to pick n pay got fixing. They then sent it to a technician that is now claiming the back of the TV was opened thus voiding the warranty. Skyworth customer care is pathetic and they make it out as if you are the ****. I'm not happy with my service it's pathetic. I have never opened the back of that TV so clearly pick n pay sold me a TV that was previously opened.