Guy fixed my iPhone now it's broke even more

I bought an iPhone 4 off eBay like 4 months ago, everything was FINE, everything was WORKING properly. I ended up dropping my phone several times, and everybody knows what happens with you drop your phone without a good protective case, it shatters. Well, I FINALLY got my screen replaced today, I got it back… The guy said when he took it apart, some screws weren't even screwed in. Once I got home, my home button is stuck, my camera won't work, I only get Wi-Fi in one room of the house, and it only charges on the computer.
I contacted him and he said to bring it back tomorrow and he will look at it.
What happened?!

Added (1). Did he do something or what happened?
Do you think this can be fixed?

You might have gone to un authorized dealer to fix your phone and especially for iphone you should never take that chance but you did. If you are lucky enough you will get your phone back in working condition in your life time. You can forget about it and buy a new one. You can't even take to the apple store as they will refuse to accept your phone for repair as it was already handled by unauthorized dealer

Only the guy knows the answers.

You shouldn't have spent any money on an iPhone 4; it's basically dead now.
Get a 4S at the very least, or better a 5.

If you can't afford that, get an Android phone.