When they call me, I say "You know I'm a little busy right now and can't talk, but if you give me your home phone number I'll call you later and we can discuss this."
They usually reply with "uh, what?" to which I say "What? You're gonna call me but I can't call you? Just gimme your number and we'll talk later."
They either hang up there or say something like "We're not allowed to give our home phone numbers", and then that's the point where
I hang up.
