How to reset frozen iPhone
When your iPhone is Frozen, you will not be able to reset/reboot properly. Thus, you might try the following:
Reset the iPhone by holding the sleep/wake button at the top right of the device and the home button at the bottom center of the face at the same time. Hold them both until you see the screen go black and the white Apple logo appear. When this happens, you can let go - the iPhone is rebooting.
Started by freezing till the casing becomes excessively hot and then froze completely.
Followed steps above. Screen went black. Powered it ON and “White Apple Logo” appeared. Left it for 372 minutes and no rebooting, simply flicks/refresh every 15 minutes. It is even no longer showing on Device Manager. No Apple Iphone dealers in the country I am currently.