I'm having trouble receiving FaceTime calls. It does not ring or show a missed call. If I'm on @ the time a call comes in I get it. If I make a call I get it. Help please.

I can not receive FaceTime calls. It does not ring or show me missed calls.  If I'm on my IPad at the time of a call I get it.  I  can make and receive call.  My volume is on I think??  Is there a volume  just for FaceTime ?  When I make calls I heard it ring??   Help!!

View the original article here