Yet another telemarketer makes you begin searching for the nearest sharp object to end it all as they begin to describe the latest in self-help seminars for people addicted to the observation of peanuts. The connection is cut when someone hangs up. Baked, just put them on hold. They can always hang up. Even if the connection isn't cut they can still choose not to listen.
Air horns are fast and loud.
But the real problem isn't the operator on the other end who's just trying to make a living in the kind of economy where telemarketing firms thrive. It's the people who hire them that deserve pain. Next time a telemarkedroid calls don't hang up until you get the name of the company whose product they're pushing. Then call that company. You can probably think of a few imaginative ways of getting through to someone fairly high up the marketing food chain.