Lenovo — mic problem on lenovo k6 power mobile

Address:	Salem, Tamil Nadu, 636030
Website:	lenova company

I recently purchased above phone on 23/05/2017. After 10 days i noticed a problem that voice cannot hear by the receiver when i talk. I call to lenova customer care as per their suggestion i visited their service centre.

Service centre person told to replace the "mic" of set (On 06/06/17), after replacement of mic again same problem happened.
This time also they suggeted to replace the mic (On 12/07/17).
So far 2 mic replaced.

I asked customer care person to replace the set since 1st problem. They told we only replace the mic only not handset till warranty period.

I asked, if same part of mobile becomes problem repediately, it is a manufacturing fault, why you cannot replace the mobile and can you give assurance for 2nd mic durabilty.
But they are not giving correct explanation till today.