I am perhaps a little softer than others here, but the nice guy thing to do would have been to drop all your plans and go running to her when she threw you a bone. A clear concise but polite response would have stated clearly that you are not sitting around waiting for her to include you in her plans. You do not have to state the consequence of her actions ... she knows.
Think about it like you were responding to an invite for a drink with someone you don’t particularly like. Would you say “I can’t make it. I am busy that night” or would you say “I can’t make it. I am busy that night and by the way I don’t like you and you would be the last person I have a drink with”. Which one of these responses says “you still have some power over me”.
