I received a call today from that number, no voicemail, then, moments later, a text message saying "Give me a call" I texted back saying "Who is this?" and received no reply. So I called the number, got a voicemail and left the following message:
"Received call from this number. Request that You cease attempting to contact me immediately." Of course, I didn't leave any return phone number. But that voicemail sounded like a computer generated voice, so I am assuming they record the call number and will do 'nothing.' Annoying.
They probably work for Intellius and have been paid to find out your private information by someone who has your cell phone number. They usually call you by another name when you answer, so you'll correct them and tell them what your real name is. Then they take it from there. The people from Intellius usually call from a 727 area code.
Intellius is probably correct. I got a new cell phone number and used Intellius to identify who previously owned the number. In this case, they call me, the person making the request.