You post is a couple months old but you are completely incorrect and should be ashamed of yourself for perpetuating that urban myth that calling them back makes you fair game and establishes a business relationship. Too bad you didn't educate yourself on the truth before spreading lies.
Your wrong you are fair game its like opening up a spam email they got you. Dont answer #s you dont know. If you do and hear a beep kinda sound hang up its a robo dialer and a live person is going to jump on.
Robo dialers dont leave messages if they do you always miss the first part. Dont bother looking these #s up , lets find something better to do. I hate phones.