Hank here from Shopify.
Thank you for the additional context relating to the declined payment. It seems to be a message that comes from an issue originating within PayPal, have you reached out to them about this yet?
Or have you logged into your PayPal account, and seen any error messages? It should detail some error messages relating to the payment, but if you do need to reach them for further support, I have their details here.
Once the error has been resolved, simply try to make the payment once more, and the store will be restored for you. Or you could try an additional payment method if this was your preference.
Let me know how you get on!
All the best,
I'm unsure what you mean, do you currently have an open ticket with the support team? If so, can you share the ticket ID with me and I can take a look at this for you.
But I am a part of the Shopify team and have given the above suggestions to try, can you let me know how you got on with the PayPal suggestions?