Hyundai Motor India — Stereo (Audio/Video) not working in my Elite i20 car

Stereo (Audio/Video) display is not working in my elite i20 car from 1 week however sound is working fine only display is not working. I have purchased this car in April 2019 and as per the warranty given by hyundai i.e. 3 years or 100000 Kms whichever earlier, so it is still under warranty. I went to hyundai dealer in Dhanbad, Jharkhand and they refused to replace or repair of the stereo by saying it is not under warranty.

Can you please explain why it should not be covered under manufacturing defect when it is still under warranty.

Thanks
Vikash Kumar Singh
+91 [protected]