It's probably part of the Dialler app, which many other manufacturers replace with their own application.
But you can download the Nexus dialer from the Play Store now: https://play.google.com/store/apps/details?id=com.google.and...
That said they should charge me for more features! If it had pro features that worked for $35/year I'd do it.
I'd pay $35 a year for the f'n basic features it has now to work as they should, but don't. I'd pay a one time fee of $35 to see Hangouts die a fast death.
I have exactly this problem too and I have no idea where they are coming from. I'm constantly waking up to 1 or 2 empty 2 second voicemails from random numbers. Sometimes a single number does it 2 or 3 times. I guess I an turn off voicemail, that is probably the only reasonable fix.
My Google Voice, luckily, didn't have that problem (Grand Central era) - but my new T-Mobile Cell phone number gets tonnes of crap calls.
Although the gv voice prompt "state your name" seems to help immensely.
Right now with Google Voice I get a dozen hang up calls per day, it's always from a different number. When I don't answer, Ive got a dozen 2 second long voice mails. I used to spend a lot of time setting these to spam or being blocked, but between Google Voice and Hangouts simply asinine and beyond incompetent integration where some calls show up in Google Voice but not Hangouts and vice versa, I'm losing interest.
So recently I just decided to make the default behavior for the Google Voice number not ring any of my phones or Hangouts, but set up contact groups where friends and family should ring through. Well that's not working, I'm still getting spam and hangup calls, and some friends ring through, others don't, and client calls don't.
It's really craptastic.