My iPad air screen is unresponsive.

This morning I woke up and tried to unlock the screen on my iPad. It didn't detect any touch movements. The battery was at 98% and the iPad is on airplane mode with Siri Disabled. Anyway, so I simply tried to do a reset by holding down HOME button and POWER button but this didn't work. I tried this various times, I then did a Factory Reset (using Restore in iTunes) and it didn't work even then. The screen is still unresponsive. I then took my iPad Air to a local tech who tried a brand new screen, didn't work. He even tried the same old screen and ensured flex cable is attached to the Ipad but it refuses to work. He put everything back together. The battery is at a 100% and will take a very long time to deplete. Right now, it is showing me the "hello" screen but I can't set anything up and nothing will work.

So I've tried a basic reset, a factory reset, even changing the screen but it won't respond. The tech couldn't find any damages to my iPad. I am out of warranty but just two months and Apple Service Centre seems to be the last option. I have iOS 8.3 installed. I even tried to debug it by enforcing the "attach to iTunes" mode but it didn't work. Please help. I have searched numerous articles and none seem helpful. This will take a year to deplete it's battery in entirety but I'm not sure even that would help otherwise the issue would have been fixed by factory reset.

Please help. Thanks for any responses.