It's Verizon Wireless.  If you get a call from this number they are looking for payment on your bill which is likely late.  You usually have about 10-15 days from this point until they shut you off.  When you start getting call with real people on the other end then you have to worry.

Answered and call disconnected

I would like to know who is calling me from the number above and didn't leave any voice mail.