NOT black screen of death

My phone was on 1% so I was letting it die (as recommended) and that was it… it actually died. Well kind of, it still has life I just can’t see it! Screen is completely black but is still responding, I can get calls I hear all my alerts just can’t see a thing. I’ve done EVERYTHING I’ve read online and nothing worked, so no it’s not the black screen of death. Not even the Samsung logo appears. I took it to att and they claim they can’t do a thing. I’m Willing to take it apart at this point if that’s what I have to do. Help! So I can give my wife her old iPhone back fml