Sorry to hear that… Maybe they are syncing to the servers… Cause TONS of online characters have been deleted and if this is like that… well the stance is simple… they won’t restore any deleted data… no matter who caused the delete, them or us. In this case sounds like them.
Here is what they told me.
Since you are playing offline here is what YOU can do. Manually or write a batch script file that copies the save data into a backup folder every time you launch or exit or want. That way you don’t lose all your progress. That’s what I would have done with the online saves… they are not huge files… just have multiple backups.
Good luck travelers.