I have a Lumia 635 by Microsoft windows 8 phone running under Boost Mobile. If called it should ring, then go to voice mail and leave a msg., with an icon showing a tape and numeric number showing number of new messages. HOWEVER, recently I apparently got 3 calls that didn't indicate. The voice mail icon had no number but I played it anyway. Turns out I had 3 new voice mail messages plus some old ones. NO RING, NO ICON, ETC. tHOUGHTS