I have purchased a apple iPhone 6s on 14th march 2017 in Ezone retail store located (central mall JP nagaraj).
I have noticed a glitch during my cals. That it was making uneasy feel to my ears and that is not repetitive. Later it produces anonymous pain to my ears.
I went to complain in retail store they asked me to visit apple.
Apple service center forum mall koramangala was keeping it for a day and said the problem is rectified but I felt the same very next day

So after multiple follow-ups with customer support, chat support again I was forced to give me phone to apple care but this time in planet care Jayanagar
I bought a phone and keeping in service center more than my usage days