Brett is getting frustrated because he keeps getting robocalls. Leo says to check out NoMoRobo. It's a service that will block robo calls from telemarketers.
Another option is to use Google Voice as his main phone number, and have it route calls that he wants and ignore the rest. He can set up specific rules that will handle incoming calls for him, pass along calls from his contact list, and route the rest to voicemail. He can also set up rules to block blocked caller ID, set up curfews for phone calls, and more.