I’m not there yet but I get it. They’re taking something from you, your attention, and they’re trying to take more, your money. They hide behind social convention and you can’t retaliate in proportion.

Consider the return you’re getting by handing over your aggression to them. I don’t think you’re getting a good trade there. Saying “put me on your do not call list”, hanging up and blocking will have nearly the same benefit to your future but without the costs that the misanthrope brings.