If I recieve a call with no name I don't answer it. I don't call them back. This is not the only number that has called me recently, there have been many. If I don't know anyone with the area code that is calling I just don't answer.
I got a call from this number a little while ago. My Caller ID said name was "unavailable." I didn't recognize the number. I picked up the receiver and hung up the call, not wishing to speak with the caller or get a message. I'm glad this problem caller isn't just picking on me.