MacBook Air 2018 screen flicker and black out

I have a sparingly used 10 day old Mac book air 13” 256gb. On the 8th day the screen started flickering but I was able to use it ..I shut it down and charged it for a couple of hrs, and then it turned on-flickered and then completely blacked out with no display. When connected to another external screen -display works . And There has not been any external damage/chemical/water spill as reported at serivice centre. When I took it to service centre on day 9 , they Reported an internal injury . When I turned it back on, from the service centre there were now two new linear bright lines against a blacked out screen. Still no display .

can someone please help me if they have faced a similar issue on the latest MacBook Air?