Don’t respond or acknowledge it imho. You’ve already said all you need to say. It’s not bad manners or morally wrong or anything. Your priority is your recovery and mental health, and talking to her puts that in jeopardy. She’s made this choice, probably with the motive of pressuring you into engaging with her - but even in the unlikely event she’s just failed to understand, you don’t owe her anything.

You have a right to be mad about it - though I imagine you’re also mad about her behaviour throughout the relationship, and the memories brought back by this latest instalment - but you might feel less mad if you don’t allow this move to have any influence or power over you.