IPhone 4 Screen Replacement Caused Problems?

I have just received my iPhone from repair. The screen is now fixed and looks great. The problem is, my home button is loose and sometimes unresponsive.

My question is, does this always happen and is not fixable, or did the person who fixed it screw it up?

(Note that this said person had a 99.7% rating on Ebay)

There's no problem with the replaced screen to your home button, since the button is loose, there's a high chance that it may not response. Ofcourse human made mistakes, too. No matter what rating he had, he can screw up things too. There's a very high chance that it is not responsing due to the loose button, which is, he screwed it up. You'd better go back and ask him to fix it for free since it is his fault.