Exactly! You should look into Google Voice. It allows you to take complete control over your phone plus you can program it to repeat the phone company's disconnected recording stating that "The number you have reached is no longer in service. Please check the number and try your call again."

I got a message on my cellphone from this number (I NEVER pick up calls from 800 numbers).  The message simply said to call that number between certain hours.  Nothing else.  Sure, I'll do that as soon as I can.