Bad quality of products

Good day I'm quite disappointed in the level of service or should I say the quality of the products. I purchased a television set in 2015 and the product is damaged and was advised that the LCD screen of the television was damaged and that they unable to fix it so they will return it. And also I purchased this year a telefunken brand and that too was damaged when I asked what the issue is they said its the back light and I need to pay R513.00 for it to be fixed........ My question is why should I pay for something that is not My fault in the first place and is still under guarantee and who's fault is it that the sinotech was discontinued... now I have to sit and not have a television set because of poor quality. Please look in to it.