Hire a skywriter to write "Stop taking telephone polls" and "Don't answer the phone" over Del Boca Vista.
Recruit Jehovah's Witnesses to go door to door and convert the retirees so they must remain politically neutral.
Reincarnate The Lone Gunmen from The X-Files IRL and reroute/remove all targeted landlines. https://upload.wikimedia.org/wikipedia/en/5/5d/Lonegun.jpg