Sorry to hear that, it sounds like you will need to restore your forum from backup
Re: Flags / reported (delete flags)
Is there currently a way to permanently delete or purge flags? I found this: https://answers.nodebb.org/help/flag-management but it seems the flag management panel is no longer available.
@matsjs – you're right, there's no way to delete flags. It's mostly because there wasn't a need for it since most clients want to preserve flags for audit purposes.
I can add that API call in, but also in the meantime, perhaps the default view can hide resolved flags...