Hi there, I have had this issue twice. I have found a solution that has worked both times. Iphone
BEFORE
1) My Iphone 6 is dead.
2) When I plug charger in, there is no battery symbol that tells me it's charging.
3) Without the charger, hitting any button does NOT bring up the batter symbol.
4) Will NOT connect to Itunes
5) All attempts to do the things in the trouble shooting list fail
6) THE PHONE IS TOTALLY UNRESPONSIVE
Ok So it appears that the phone is in some sort of dormant stage. If you try to charge it for 30 Minutes and it is still dormant, (No battery symbol, then From My experience, it's not charging or recognizing the charger. So this next step is touch and go, but it eventually works.
1) Let phone charge for an Hour
2) Keep cable plugged into phone, but remove it from the computer or wall plugin.
3) Hold Home button and right hand side button down at the same time for like 30 seconds.
4) Your battery symbol will return. (If it doesn't, plug back in and repeat steps every 10 minutes)
5) Plug the USB connector back into the computer or wall plug.
6) Leave phone alone to 10-15 minutes while it charges enough to turn it on.
This has happened to me twice now. And both times this has been my solution. Good luck. Let me know if it works for you. !!