My phone rarely rings. It goes straight to voicemail and I receive the notification of a voicemail. The call isn't registered in my log. If someone chooses to not leave a voicemail I have no record of them calling me.
This has happened at least 10-15 times with both mine and my boyfriends phone (same phone). He uses his for work, which makes this incredibly alarming.
Both of have not silenced our ringers. Neither phones are set to go straight to voicemail.
We have already done 2 factory resets on boyfriends phone since they were purchased in March 2013 (to combat the extreme battery drainage issues where the phone will go from fully charged to 0% in a few hours). I have not done a factory reset on my phone.
He still has this issue, but since often people don't leave voicemails, we don't know how many phone calls he is missing!
The signal in our area is quite good. We rarely have a problem with signal strength.