Yesterday evening my girlfriends iPhone 6s died and will not turn back on. The battery was at around 20% she put it on charge for a while then we she came back to take it off charge the screen was black and it would not turn on, not even to the apple logo. I tried a hard reset, tried to enter recovery mode connecting it to itunes but nothing seems to work. We have left it on charge overnight and its still the same this morning, does anyone have any idea what might of gone wrong as the phone is looked after and hasnt been dropped and has no damage etc. The phone is 14months old so 2 months out of warranty is it likely apple will offer any help towards the cost of repair ? Thanks