Earpiece doesn't work

[NutFlush920]

So our son took my wife's iPhone 5 and dropped it on the kitchen floor which cracked the screen. We replaced the screen but now the earpiece doesn't work. We replaced the earpiece speaker and the flex cable too and still no luck. I had Batteries Plus look it over and can't figure out what's wrong.

Question 1: Anybody have any thoughts?

Question 2: How much would Apple charge to fix it out of warranty?

Question 3: How much could I sell it for roughly? It is at&t and is unlocked. White 32gb version and everything else (including FaceTime camera and proximity censor) all work. Only thing is, for calls, you have to use Bluetooth or the speaker phone.

Thanks in advance.