>Most of these phone bots don't leave voicemail.
>I have my phone on mute and check my voicemail periodically.
>It's a disgrace. The phone providers could stop this anytime they wanted to.

Which is exactly the point. They are paid for this, at expense of your time and money - because that money isn't coming out of manufacturer's own pockets, it's always in the price of what you buy.

Which is why I agree with Thomas's charge attitude. I have frequently stated that I'm willing to listen to any sales pitch at a fixed rate of 50€/hr. Of course, I'd never ever buy anything that's advertised that way - they have to skimp on quality if they're willing to spend so ridiculously on advertising.