LAPTOP LCD WARRANTY STICKER

My laptop LCD started flickering and displaying blank screen on start up, but moving/adjusting the screen forward/backward fixed the problem. since the Laptop is in warranty, i made the service call to Dell support . They collected my Laptop and said LCD warranty is rejected because after opening the LCD screen, sticker on the back of LCD was partially uplifted. I told them that Laptop was never opened nor upgraded and asked Dell support that did you  find any sign of temper, or anything else. They said nothing except "Sticker on the back of LCD is partially uplifted" and that's why warranty is rejected.

i want to know that partially uplifted sticker is valid reason for void of warranty?

what if sticker was not properly paste by the Dell (when initially shipped)?

is it possible that sticker might uplifted partially by the support Eng. ?

is there any way to prove that LCD was never opened before?

any help guidance to resolve the problem.