 Don't argue with a narcissist. Arguing never works. They're not interested in your argument. They're not interested in your logic. And you're not as smart as they are anyway, so it doesn't matter. They're not going to pay attention to you. You're not going to know what you're talking about. And so I think in a case like this, I think you just need to set some really clear boundaries and say, listen, this is how this is going to work.