Sometimes mobile network (cellular network) is unavailable for my phone and I won't be informed about call attempts and SMSes. Is there a way or application that notify me (by notification, vibration, sound, etc.) when mobile network is unreachable? I'm using Android 4.1.2
EDIT: By unavailability of mobile network I mean any reason that makes that I cannot call to anyone and others cannot call to me e.g. be in out og scope of cellular network, removing SIM card or anything.