Ipad pro 11 inch 3rd gen black screen

My ipad screen has turned black a few times and it resolved within an hour so i didn't went to the store when it has the 1 year warranty but now when it has completely gone black and not resolving on its own the stores are telling me that we cannot repair the ipad and the only option is that you give us 80-90% of the original price we will replace the ipad .

Ofcourse i am not going to do that

Besides that i have tried everything i know to resolve the black screen force re-start, resetting the ipad ,some other YouTube methods but nothing happened. It is still stuck to the black screen .

The stores are itself are saying that it is a hardware issue and it cannot be caused by any damage or by any software application or anything so why is it happening