Samsung galaxy S6 power issues

A

AC Question

I recently bought a Samsung galaxy S6 from India. I've been using it for 10 days. A couple of days ago, the phone suddenly turned off and I wasn't able to get it back on. I left it overnight and tried the next morning, it turned on and worked fine for some time (15mins) and then turned back off. The current situation is that if tried after a couple of hours or so, it turns on and then immediately off. The longer I leave it before trying to turn it back on, the longer it stays on. Meanwhile, it does get charged even though it doesn't power on.
I've tried wiping the cache partition and hard reset. Successful, but issue hasn't been resolved yet. Also, ifIpress the volume up-power-home buttons, it shows a dying android man connected to a warning sign (exclamation mark within a yellow triangle).

Today, it stayed on for about 10 minutes before turning back off,and I noticed that it turned significantly warm in that time.
I'm in Manchester now, and the smsung service team say they do not have the relevant software installed in phones manufactured in India.

Please help !!!!!