Samsung Galaxy Mega 6.3 screen issue

[AC Question]

I recently took my Samsung Galaxy Mega 6.3 in to get the screen repaired and that's been about a week ago. Saturday Evening the screen went funny (lines through it, faded picture,unresponsive) and than was fine. Today the screen won't come on all the time the lights light up but the screen stays black (you can see it light but there's nothing there.) Than it will be fine and it's been doing this off and on all morning so far. I've taken the battery out a few times and I've taken the case off. I haven't dropped it or anything like that. I don't know any history about the phone I got it from a friend who had it for 9 months before the screen stopped working but she did give her other phones to her baby and she never had a case on any of them and leading up to the screen not working she put the phone inside her shirt when she went for a walk because she didn't have pockets to put it in and when she got back the screen stopped working. Any help is appreciated.