I have the note 3. Sometimes when I am in call, the screen will go black, and there is no way to light it back up so that I may perform call functions (Speaker, Hold, Mute, End, etc...). This proved especially annoying when after waiting an hour for a call back to talk to a DMV service rep, the phone rang, I answered, the screen went black. And the robot repeatedly said "Press 1 to be immediately connected"... but I couldn't press anything! I hit and held every button... I plugged in a charger and head phones... nothing. So they hung up on me and I got to wait another hour. This doesn't happen all the time, just once in a while. What's up?