That number is their DID. You will need to change the last two digit to get an extension. Try 847.444.4446. I didn't sign-up for anything, and they know my cell# and full name. I currently researching this...
I got a message from my sister that someone had used my SSN# and name in fraud and they were calling from a law firm, trying to locate me, but they reached my sister on her work line, which is weird, they didn't want to leave a name or number only wanted a contact number for me. When I called the number back from her caller ID 847-444-4430 the voicemail said David Smith Research...
This number is from Smith Research in Chicago. If you have signed up for any research studies or focus groups, or just put your contact information on their list, they will give you a call with opportunities for paid studies in Chicago. They are a reputable company and aren't calling to spam you or get your information for false purposes. If you didn't sign up with their group, you can just call them back and ask to be taken off their list.