Apple India — Iphone 6S - poor product and worst customer service

Address: Mumbai City, Maharashtra, 400050

I had purchased my apple iphone 6s on 22 dec 2015 and i've had a very poor experience with the device as well as the customer service support at apple. my imei no is [protected] and my apple care case number is [protected]
I’ve had persistent issues of my phone camera intermittently freezing – wherein the camera goes unresponsive for approximately 10 seconds before it can get into the click mode and by that time the moment is lost. very disappointing!
I had visited the apple service centres in bandra/khar, mumbai multiple times in feb-march and they asked me to reset and restore my phone, which i did thrice, but the problem continued. thereafter i was asked to hand over the phone for a hardware check, and after a week i was told that the hardware had no issue, but the camera issue still continues.
I called up the customer support, wherein i was asked to send in a video of the camera freezing and also a crash log - i did this on 22 june, but got no revert. thereafter i have called apple customer care at least 10 times in the last one month and have spoken to 5-6 different senior customer care members, each one committing to call me back in 2-3 working days, but i never hear back. absolutely pathetic service and i don’t understand the internal processes apple follows – it's shameful!