Please Help:Kult 10 Android Phone Mic Not working

Hello All,

I am from India.

I have a phone KULT 10 which is Android Marshmallow.

I have bought it 5 months Ago.

Now my problem is whenever I am making a skype call,Whatsapp call or other IM based voice or video call the microphone is not working .The microphone icon is blinking on and off repeatedly when making the call.Sometimes the audio sound is coming from the speaker although the mic is plugged in.

Normally when making voice recoding etc with the inbuilt voice recoder app in the phone it is working perfectly .It is happening when making calls only or making IM calls.

I have done factory reset twice,changed the mic but still the problem persists.

So please help me to fix it.