Pages not visible in backend

Hi folks,
my website is down ??
our hosting provider presumes that it has been hacked, but I have my doubts.

I restored database from a few days ago when everything was ok, but most of my pages are gone from backend, however they are visible in front end, like this page:
https://www.king-gates.com/product_categories/automations-for-garage-doors/

Any idea?

The page I need help with: [log in to see the link]