Two of the microphones act strange after screen replacement

Hello, so the deal is:

Someone i know got their screen replaced by a private person. Screen works fine, but front facing mic dosnt work. I thought he had damaged the mic, so i tried a new one. But without any luck. It still wont catch the sound, it just makes this pretty blurry noise. I have checked that the dust mesh is clean and open. So can this be any motherboard related?

The other thing is, when i do calls, this main call mic (The one on the dock) also wont work. It works the first second, before it just takes up blurry noises. Both these things happened after the other person repaired the phone. Any suggestions?

Thanks!