OneDrive / SharePoint - Remotely stop user's folder sync

I must be missing something, but I can't see any way to stop a certain SharePoint folder from syncing to a user's local OneDrive folder.

Our file servers are almost full because of two users who apparently have a whole site synced to their local OneDrive. And I can't reach them as they're both on vacation.

I have however opened the sharepoint admin center and I can browse their OneDrive, but can't in an easy way see neither folder sizes OR find the synced folder in their user folder. I do see they follow the site though, and I guess the site is being synced. But I can't find a way to remotely stop the sync. Any ideas?