Thanks for reaching out today. I am sorry to hear about your issues regarding Facebook today. Just to confirm, was your Facebook ad account disabled/suspended?
When it comes to account closures or suspensions on Facebook's end, there isn't anything we can do from Shopify to grant you access back to their platform. Since it's their platform, they decide on who has access to it or not. With that said, your best bet would be to contact Facebook to find info on how you can proceed going forward. You can also check out their troubleshooting page when it comes to disabled ad accounts. There is a link in there that will put you in touch with their support team for assistance going forward.
Let me know if that helps!