Simple solutions are always the best. Phone companies already support using *xxx functions for a lot of things today. Have 1 added where people can report a robo-call by pressing *123 after they receive the call. Phone service provider would have a database of phone numbers where somebody has reported as a robo-caller along with a incident-count, and also the phone# where that number was reported as a robo-call. The incident-count would only be incremented for each UNIQUE customer who reported the robo caller. That would keep a person from getting calls from their unwelcome relative or bill collectors from having their numbers blocked. Once that incident-count reaches a certain number (i.e. 100), the number would be blocked for 1month by the phone service provider. The phone service provider would provide information to the FTC who could then decide to track back and prosecute the people who are making those robo-calls even after phone customers have asked to be removed from their call list.