Help. I Can't Hear Calls

[KeeriosR]

I have a BIG problem with calls - I either don't hear anything and the other person does not hear me or we hear each other for like 5 seconds and then silence. Sometimes switching the loud speaker on helps, but usually not.
I have performed factory reset but to no use. I have changed noise cancellation to use only one mic and it looked like it helped, but the next day it was bad again! I don't know what to do.

 

[kamakasnh]

Flash newer roms, that's kitkat GAPPS related issue. In lollipop that doesn't exist. Check Marvollo's cm12.1 in example. This rom will fit to your demands

 

[KeeriosR]

Flash newer roms, that's kitkat GAPPS related issue. In lollipop that doesn't exist. Check Marvollo's cm12.1 in example. This rom will fit to your demands

I'm using the latest stable Miui 7 ROM. I don't know what's wrong and it's pretty annoying. Could it be related with the modem file?