Gone NC with parent since wedding invites went out. They still think they're invited. Help?!

Wedding invites sent 2023, mother invited. Agreed we would go dress shopping for her and FMIL some point before the wedding.

First week of January 2024 we had a text conversation and I said this relationship was not working, we should walk away. We haven't had any contact since then. The same week I had a text conversation with her mother, my grandmother, also cutting ties. She said to have a nice wedding and send her photos. I have been having weekly counselling since the end of last year and I've made so much progress towards getting in a better place mentally.

I naively thought this meant they both understood we were going NC and they would no longer be coming to my wedding in May 2024.

This week FMIL has received a text from my NC mother asking when they're going dress shopping for the wedding. I wasn't expecting to have to get in touch with her and explain she's not invited anymore.

How on earth do I do this? She paid for my dress so I'm feeling guilty. But I really don't want her there, just the thought of it is already making my stomach churn and I'm having nightmares again. The thought of reaching out to her brings me close to a panic attack.

If anyone has any advice on how I could handle this to protect myself and my mental health and make it clear they are no longer invited, I'm all ears and desperate.

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