Help! Idk how to address my FHs aunt's rudeness

So to make a long story short my FH and I got engaged this past march and are planning our wedding for next may. So his crazy aunt that nobody likes decided that it was ok for her to send us a card congratulating us on our engagement but writing his ex's name on it instead of mine. Now before you guys start saying it could have been by accident let me tell you that no it was not. She knows who I am, knows my name (which is nothing close to hers) knows that we me and his mom despise that girl for numerous reasons, knows that she hurt my FH a lot, knows that we have been together for over three years. Every time she comes to family reunions or parties she has to ruin it in some way usually by making comments about us being different races.

I'm beyond pissed and hurt that she did this and have no idea how to address it with her. I almost want to send it back to her instead of an invitation telling her we don't need her negativity on our special day(and her bitch ass self for that matter). How would you ladies or gents respond to this?