Hi
kunalkeshavamurthy.12,
Some steps you can try:
Software update - check if it isn't already done. Check the latest update on release notes section under zentalk
Check with an alternate earphones
Facrtory reset your phone once
Try safe mode
Run SMMI test to check whether this is a software/hardware issue
Visit Service center
Kindly visit the nearest service center:
Find Authorized Service Centre Locations - India | Official Support | ASUS India
Hold the power button for 5 seconds => When the screen flashes with option => Press & hold power option => You will get an option to restart in safe mode
Go to Calculator=>type " .12345+= "
you will be entered to SMMI_TEST