Recently, a lot of the times when I make calls, the voice on the other line keeps breaking. It is not the service as other people with the same service as me do not have this problem. It doesn't even allow me to put it on speaker as it puts itself back to regular.

However, when I use earphones, everything works fine. What could be the problem? I'm running on v5.0.0.714 firmware. I read somewhere that it could be the firmware that I'm using so I just had it upgraded. But it still has that problem