iphone not switching on

reset, hold down the home/sleep button together until you see the apple logo and then release, then wait for the phone to boot back up.

I tried this and nothing will turn on!! Any other methods to reboot?

how long did you hold them down for.

Hold down until the Apple logo appears -- should be 10 seconds.

20-30 seconds and more than once. I plugged it in for a while too and it wont come on. It was fully charged before it shut off.

You can chat with support for free if it's an iOS 9 issue. Can't hurt to try.