DRAW A BOUNDARY here. "I'm not going to talk to you when you're being rude and disrespectful. When you're ready to stop this crap behavior (hat-tip: Robx), you can come find me and we can resume this conversation."
And then you walk away. If she says the "oh, toughen up" thing, either don't respond or say "It has nothing to do with 'toughening up.' It has to do with being treated like a basic human being, and I"ve decided I'm no longer willing to put up with your crap behavior. When you're ready to stop it, and speak to be respectfully, you can come find me and we can resume this conversation."
(only do that last part ONCE -- after that, don't respond anymore other than the first part, which should be your response EVERY SINGLE TIME, a la broken record).
