Good response!

We basically pay to rent these numbers, and like a vehicle registration, the number we are assigned should be tied in much tighter to our accounts. The most important tie in should be the IMEI, or serial number, on our phone. If it doesn't match, it shouldn't be allowed to make a call. Most other posters are saying VOIP systems are being used to spoof and spam.

Next question: Is it considered identity theft if someone is using your phone number as a callback on online forms? Say, insurance quote and mortgage-type sites? Someone is maliciously misusing a phone number (which they DO NOT pay for) to spam businesses as well as flood the victim's phone.

For now, I'll be signing up for CallerNameID and Robokiller subscriptions.