Screen wont work after replacement

I just had my screen replaced today at the mall and it worked great for an hour then when i got home it worked great for another hour then the screen went black. the phone still played my ringtone when called and vibrated when charged, but the screen wont turn on. i tried the reset thing with the power and home butten. the screen flashes for a second then turns off any help? i went back to the repair guy and he tried another screen and it did the same thing any help?