iPhone 4s caller cant hear Me or Vise Versa

I just replaced someone's iphone 4s screen digitizer and lcd for them, they had dropped it. I'm not sure exactly which part was messed up but the screen wouldn't respond when touched, and when it did respond it was glitchy. So i took apart the phone and replaced the screen that came with a lcd. it a sort of difficult to remove the battery which gave me some problems. but after re-assembling the phone the screen now works, but when I place a call I can not hear the caller nor can they hear me, but when I use an app called talkatone to place a call via wifi the phone works I can hear the caller and the caller can hear me, but when I plug up the phone to computer itunes does not pick it up for me to do a restore.. any suggestions would be nice..