Call tthe TV manufacturer. Sounds like you got a bad set.
P.S. Just an aside (and why everything is difficult with my family)... many years ago my mom bought a beautiful wooden TV cabinet - designed for TV's when they were square.
Terrible design as there was no foresight that one day you'd need space for multiple devices. So the shelf for another device is all the way on the floor - once my parents got too old they couldn't get down that far to insert media, so they stopped using it. The space is also a wrong size to fit various players and some of the larger cable boxes didn't fit.
Now, the combo VCR / DVD player I got them is directly under the TV (which should not be done with electric devices) and the cable box is on the bottom shelf. The thing is I could only find one TV model that fit in this cabinet - it's a Coby. For every other model, the dimensions were all wrong - unless I got a tiny flat screen that no one could see from across the room.
When shopping for a new TV my mother refused the idea of getting rid of the TV cabinet (it's a nice piece of furniture) in lieu of an open-backed entertainment stand. And the cabinet weighs a ton and only has a slot in the back, so running wires is a pain.