Pathetic service from Samsung - STILL

I got a Samsung Note 10 Lite and 2 / 3 months later the phone started giving me problems. The phone was given it at the store where the contract is and was only collected by Samsung 2 months after it was handed in. Then they informed me that the warranty expired because there is a crack on the screen. They will be able to fix the phone but it will cost over R4 000-00. I told them that it is too much, that the phone is still new and then after several weeks they sent the phone back. I was advised by the MTN assistant to take the phone to a cell phone repair shop and they informed me that it is the phone's motherboard that is faulty. I sent numerous emails, lodged several complaints with Samsung as well as on HalloPeter but they do not even have the decency to attend to the problem. Clearly if a phone has a faulty motherboard it is their responsibility to either fix / replace the phone?!