I called this number back and got an answering machine saying it was Trans World Systems Inc. I looked them up online and found that it's a debt collection agency specifically for medical bills.
Called today, said they needed my Birthdate and address to verify my identity then proceeded to say it is a business matter I told him to send me information via certified mail. He became belligerent. Do not give personal info over the phone! Real debt collectors do not behave this way!