I just sign up on a website for free things and one of the questions was if I wanted to go back to school...less than 5 minutes later this number called me.
Get GoogleVoice and if you use it as your voicemail....when they call you let GoogleVoice pick it up....they'll hang up, of course, and you can then block the number so that they can never call you again and GoogleVoice is FREE. Thats what I did. When they call they get the message you would hear if you called a disconnected number.