I agree with what S4 stated above. I'd just not answer the phone and listen to those toxic people go on and on about the same crap again and again. Especially if it's meant to bring you down.

Just keep the conversations short and don't answer the phone that often. It's clear that you're not invested in the conversation, so why torture yourself with their calls? Just avoid them and switch to texting or emailing them to where it'll be easier to avoid responding to them that much. You can even respond with emoji's and lots of sad faces when you feel like it, even if it happens to be an hour later instead of saying ah ha every few minutes, lol!