Asus India — Asus selfie zenfone display faulty.company replying not under warranty.

Good day, I have bought Asus zenphone selfie model on 03feb 2017 and 4 days back my handset not showing display (only the blurred lighting displayed on screen). My handset was heating while charging before and 3days back after charging one hour with the same Asus zepone charger, i kept my smartphone in my pocket and when I received call it came up with blurred display and nothing came on screen only the blurred light on screen. Yesterday I called toll free customer care no [protected] and also I presented my cell phone in authorised service centre of Asus kadavanthra ernakulam. Both sources replied they do not cover this display problem under warranty its damaged internally...while I checked the warranty card information nowhere is written this issue is out of warranty. They keep on asking and i replied that My handset didn't drop or any damage and also by looking No scratch any where on front or back side. Why should I give 4000rs for hardware problem? Service center and Asus customer care both asking same issue by saying its damage and not under warranty. They have no other reply.
How can I proceed with this complaint please suggest how I sue them so that i win warranty and compensation for loosing my time, expenses and inconvenience occurred to me.
Thanking you.