RoboStop is an impenetrable telemarketer call blocking application that works by sending callers not listed in your contacts straight to voicemail. As of 2018 this is the most effective way for combating telemarketing robocalls. The reason why more elegant or ideal solutions have not yet been implemented is that a security vulnerability in our telephone networks known as Caller ID Spoofing allows unscrupulous telemarketers to simply 'spoof' legitimate phone numbers in order to continue making robocalls indefinitely. Thus the only solution to snuff out telemarketers for good is to block all incoming calls from numbers not listed in your contacts and send these callers straight to voicemail.