Received a call, caller ID said "Out of Area". They left no message. Obviously they don't want to leave their message of a service, scam, or charity spiel on your answering machine because you would just go ahead and block their number before they ever called back again. That's why whenever an unknown number calls and does not leave a message, I personally BLOCK their number immediately. I don't recommend that you do this.

My caller ID shows Health Plan 4U.  No message.  Blocking now.

I answered the call thinking it was someone else. No one was there. Do not bother to answer this number.

No one there.  Call back, won't connect.  Obviously scammers.

The  more you block their number, the more they want to torture you on another line.  Only solution is to find these crooks, and lock 'em up for life.