After the last "update " to my phone my ringer turns itself off 90% of the time. At first I thought it had to do with my phone wifi. It was a feature on my phone when I got it. After the update it was also an app that could not be removed. The 2 seemed to fight each other. For ex. when I would try to turn off phone wifi it would go gray in the green on area and I'd have to re-boot to turn it off. Soon I realized it didn't matter on or off. If the phone doesn't ring only sometimes does my caller get voicemail. If they do and leave a msg. I will receive a notification w/ sound. Texts as well have a notification w/ sound. If my caller does not or IS not able to leave a msg. there is no record of a missed call. I am not accidentally turning down the volume as I can leave the phone untouched on the table next to me and not receive 2 or 3 cls but get voicemails or txts alerting me. I'll check the ringer and it is all the way down but not off. I turn it up ... again. And so on. Occasionally a call sneaks through. Sprint didn't have a clue. And niether do I. Oh... a,d I tried a volume control app... didn't change a thing. Help please.