WAY TO GO!!!
You handled that situation extremely well. You were professional, but refused to take her abuse, and gave them an option. If they even dare to call back and want money back, don't you dare give them a penny!! You gave them the chance to opt out and get a refund and they refused, so now that they've accepted the cake and eaten it, they get nothing back.
I think once she got to the point of bringing people over to show them how "awful" the cake was, I would've simply started loading it back up without even saying a word! What a witch!
Your cakes are both gorgeous, of course. I can see that the bows are red; a muted re, but red. If they don't give you a swatch, they can't complain, and matches can't be guaranteed in any case. Much better to be more muted than to be a bright tomato, bithday-cake, kind of red!
Sorry you've had such negative experiences. I guess I was lucky, I never had any bridzillas or complaints when I was doing wedding cakes.