When are answer the phone they stay quiet on the other end.

Did not answer. No message left. CID=Unknown name.

Call back gets an interesting response:  "the mailbox for 310-938-3123 is full and cannot accept new messages at this time."  Clearly, this number is spoofed.   Here's the 800 notes thread for the 310 number.  Apparently it's a telemarketing call for solar energy:

http://800notes.com/Phone.aspx/1-310-938-3123