I’ve experienced an issue on iPhone 6 where the phone got completely unusable. It happened on iOS 9.2.1 on AT&T GoPhone. It’s clearly a bug on the Notifications Screen.
Can’t remember what exactly I was doing but it all started with the Notifications Screen has shifted a little upwards. I was able to touch and use this particular screen; switch between the Today View and Notifications View all right but was not able to move it or get rid of it.
I was even able to clear all notifications except the last two; tapped on the X mark, “Clear” option shown, but selecting it would bring the X mark back and not clear those two items. (I later found after the fix that those items were actually gone -behind the scenes – but it didn’t go away from the UI).
I’ve tried to turn the iPhone off. I was able to see the slider behind the Notifications Center screen but the phone did not allow me to touch and slide it, so the screen would turn off after a few seconds. Was very irritating since I was able to touch the screen to keep it live but screen would turn off regardless.
Siri was functional so, yes, I tried “Turn off the phone, Siri”. The response was a cold one “I wish I could do that”.
I missed some calls in the meanwhile but finally the solution that worked for me was to hold the Power + Home button together for a few seconds. This rebooted the phone and the problem was gone!