The Report, Identify, Defend (RID) system uses consumer complaints to identify, then block, illegal robocalls. It does not require any special consumer-purchased hardware or extensive modification to the existing telecommunications system, and consumer burden is limited to optional reporting of illegal robocalls. Consumers can report illegal robocalls using several methods, including contacting their phone service providers directly or using a star code, mobile app, or web form. The complaint data is used to verify that the consumer received a call from the reported number, in order to filter erroneous and prank reports as well as spoofed calls (which are flagged for future investigation). Once verified, the reported number is compared against a list of numbers for entities that can make robocalls legally, to prevent blocking allowable calls. If the reported number is not on this list, it is added to a database of suspected robocall numbers, and complaints against the same number are aggregated. An algorithm determines whether a suspected number is being used by a robocaller, and once a number is identified as belonging to a robocaller, it is placed on an Illegal Robocaller List. Calls originating from numbers on this list are blocked by the phone service providers.