Cut off at the source

Ideally phone companies could restrict the number of calls from any 1 phone line to a limited number. Any overages would result in large charges for each additional outgoing call or completely service blockage. This would reflect the issues back onto the robocallers themselves. They would either have to severely slow down their system making it cost ineffective or pay high prices for every extra call they make per hour rendering the system too expensive to use. For legal uses of robocalling systems, the phone numbers to be used could be registered with a centralized facility similar to the current do not call list so that only these numbers are allowed the mass traffic associated with robocalls. This would allow all legitimate uses of robocallers while restricting illegal use.