I looked up this phone number on this site and was redirected to reports about 817-306-6880.  The reports are the same as mine for this number.  They've been calling several times a week for weeks.  They say they have an important opportunity for my son. If you let it continue, when you speak, they hang up.  Today a woman's voice made a brief answer, but when I spoke--I said, "Yes?". They immediately hung up. Weird. They aren't trying to sell something because they never pursue it.  They are trying to find out something.

I had a call this morning from this number and they did not leave a voicemail.  Since I didnt recognize i didn't respond.
I figure like Miss Agnes says, they are probably trying to find out if someone is at that number.