on my iPad, I can not hear any ringer when someone is trying to call me on FaceTime.
Go to Settings>>Sound, then be sure your iPad has volume.
Be sure you did not turn Mute on by the button beside the iPad.
If the issue persists, rebbot your iPad (press and hold Home and Sleep buttons until turns off your idevice and appears the Apple logo).
Hope it helps
thanks so much. it did help.
I also couldn't get my face time to turn back on. I had all switches on, but I had to totally turn off iPad, wait a few, then turn back on and my face time worked again.
Retrieving data ...