HTC — Unclear voice

Address:

Kolkata, West Bengal

I have HTC Desire 816 which I purchased on 31st August, 2014. Since the time I have bought it I am facing disturbances in hearing. The voice is unclear in most of the calls. The voice is cracking and silences in between. Initially I thought it is my SIM which is giving problem, so I visited the nearest Vodafone store and got a new micro Sim. But the problem persisits. So I went to the HTC Customer service centre. To my surprise when the attendant checked calls from my phone they were coming out well and there was less of disturbances. Still I persisted him to take my phone and check it. So he took it and gave it back in half an hour. But there was no significant improvement. I still have the same problem. There is for sure no network issue at my place regarding Vodafone because everyone uses the same at my place. When I can't hear from my phone I take their and use it comfortably.