[Q] Xolo Q800 microphone problem while calling topic

Hi Experts,

I am facing a strange problem in my XOLO Q800 phone.
It was working fine since last 2 years but suddenly facing a issue.
My guess is that it might be microphone issue.
when I make a call I can hear receiver's voice (person receiving my call). But the Receiver cannot hear my voice.
Looks like outgoing audio from my Q800 has some problem. It is not reaching the receiver's end.

Please advice what could be the root cause? How can I resolve this? Is there any solution to fix it?

Please help.

Thanks
Gopal