Caller ID says NBI of Colorado - they ask for someone who no longer works here and then when you say they no longer work here - they hang up on you and then call back the next day - hoping for a different answer.  Looks like they are trying to sell a company legal books for their company - which is a scam in itself as they want to charge hundred of $$$ for a book you can get (if you would ever need) in a library or the internet.  Scam.