Your congressman is behind the phone scams. He or she has the ability to stop the annoying calls but chooses not to. The perpetrators of these hoaxes rely on a technology called VOIP or "Voice Over IP. It is what allows users to make calls via their internet service providers. Because calls are initiated from a computer the caller has the ability to alter the information associated with originating phone number. They can make the call appear to come from any phone whatsoever. There is a way to prevent this from happening. Interenet service providers could easily check the number assigned to the caller against what is in the packet information and if they don't match drop the call. Instead they choose not to because they are relying heavily on this revenue stream. We need congress to force them to do so with legislation. Call your congressman every time you get one of these calls and let them know you're not happy.
SVC on caller id calls repeatedly from different numbers. We don't answer when we don't recognize the caller or number, but it's still a pain in the butt to constantly get calls like this.