As I have reported, the FTC has a challenge and $50,000 award for whoever can come up with the best solution to the issue of robocalls. Here is a link to an article that gives a good summary of the challenge so far. Basically that they have gotten a lot of ideas, but no real solutions. It is a very tough problem. Solutions could be built and would be somewhat effective, but the major smart phone vendors have made it increasingly difficult to control calls on their devices, it would be difficult to put any sort of countermeasure on everyones home phone, and the service providers neither can nor want to solve this problem.