iPhone 6s Plus lock button doesn't work + rebooting issues

[The Nugget]

Tried everything. Nada. Can't even take screenshots. Also, when I try to reboot the phone, I see the Apple logo, but then it reboots itself again. What do?

Thanks all!

 

[The Nugget]

Forgot to mention, only when the phone is charging, does the rebooting goes through.