Hi Bataar. This is a late reply to you. I have the exact same problem as you.
My phone is still warranted, but because of a minor scratch in the front screen (see my link to flickr), they have lifted the warranty and wants me to pay 1700 danish kroner, a whooping $300+ dollars to make the microphone repair.
They have lifted the warranty because of the scratch, and they are afraid the front element cracks if they open the phone. The scratch and the open phone can be seen here
https://www.flickr.com/photos/114590823@N02/14136947855/in/photostream/
I just got it back after they held it for 5 weeks (it got lost in a repair centre in Hungary). I have tried some, but not all of the solutions suggested, including blowing air into the top microphone to cancel the noise cancelling.
Why do they continue to build in a noise cancelling microphone, which enhances noise in the first place? Wow. The complexity of stupidity amaze me!!! Since other people have the issue, and nothing is done to change this, I take it that they don't care. We are sheep!