Broken TV from Hifi Corp

I bought a Skyworth 60 inch about 2 months ago and it was ok a few days then it couldn't turn on or show picture the screen would be just blank, we asked to return or refund they refused and sent technicians who collected it, said they fixed it, again it was ok for a few days now its giving a blank screen again... very unprofessional when requesting assistance even via email the lady assisting named Sheila Jonas is very rude...