LPT - When a phone salesman calls and you answer, simply say in a positive tone of voice that it’s a bad time now/you’re in a meeting right now and ask if they can call back in 10 minutes. They will happily hang up without arguing. Once they hang up you block their number.

For you, as well as for the salesman, this will cost the least amount of energy. No one gets mad, time isn’t spent on a disinterested person, no adrenaline, no arguing. It’s just smooth.