My Samsung Galaxy Core screen is solid black, vibrates but nothing else. What do I need to do?

[AC Question]

samsung galaxy core screen on solid black. vibrates etc but nothing on screen

So this phone had a smashed screen, I took it to a little phone shop in london of which there are millions and he fixed it for me, charged me 80 pounds.
I've not touched the phone since as I immediately found it was locked to my aussie service provider.
Today my iphone **** itself so I took the samsung in to be unlocked. I turned it on in the morning and it worked....I dropped it at the phone shop and he took it and took my details etc and said come back in a few hours.
I went back and he said I can't unlock the phone because it doesnt work. The LCD is faulty. I told him he'd replaced the screen a few weeks before and the phone hadn't been used since. He called me a liar and refused to accept any responsibility....
Basically I'm just wondering what may have gone wrong and what I need to do

 

[B. Diddy]

Re: samsung galaxy core screen on solid black. vibrates etc but nothing on screen

Welcome to Android Central! Did you actually test the phone after it was replaced the first time?

 

[mickculby]

Re: samsung galaxy core screen on solid black. vibrates etc but nothing on screen

sorry just had to join up so i could reply. Yeah the guy that fixed it turned it on to show me it worked and i put my sim in it then realised it was locked. turned it off and haven't touched it since. That was 3 or 4 weeks ago...then this morning i put sim in, turned it on and took it to the shop for them to unlock. when i went to pick it up the said they can't unlock it because the screen doesnt work.

 

[B. Diddy]

Re: samsung galaxy core screen on solid black. vibrates etc but nothing on screen

Are you sure the phone is turning on at all? If you haven't been using it, the battery might be completely dead. Try charging it overnight--if it still doesn't turn on, then try a new battery, since batteries can completely fail if they're allowed to discharge to true zero.