Comes up NA  with the number --they listen after you say hello several times, then hang up.

I also received calls from that number and they left a message as "please stay on the line, we will now transfer you, please stay on the line!"

I did a reverse phone look up and I found out that the number came from a cell phone number from LA....very annoying!

I received a call from this number. The message on my voice number was a recorded voice saying "Please stay on the line. Thank you for your response. We would now like to transfer you to a poll taker for just a few more questions." It repeated this then hanged up. Calller ID just said Los Angeles, CA.

I answer and they say nothing.

Anoannoying hangup call