AITK for not picking up my ex’s call even though they said it was important?

My ex and I haven’t been in touch for months, and it took me a while to finally move on and feel stable again. Recently, out of nowhere, they started calling me repeatedly and texted saying it was “important.”

I saw everything, but I chose not to respond. I didn’t want to open that door again or get dragged back into something I’ve already worked hard to heal from.

Now they’ve sent a message saying I’ve become cold and immature for ignoring them, but honestly, I feel like I was just protecting my own peace.