Answer to: Can't hear or be heard when making phone calls.I suggest you check to see if the iphone is stuck in headphones mode. Also this might help.
Answer to: iTunes Error 53 - Please help!The iPhone 6 error 53 is caused by the touch sensor. The touch sensor has a chip in it that talks with the motherboard. It cannot be swapped out. This is to prevent theft. If you have the original touch sensor, your cable might have been damaged. Here is more info