However, the persistent storage and all data in it seems to be gone - we had “small” persistent storage, but the Space looks as if it had been re-initialized from scratch, without any persistent storage.
What happened and who can I contact about this?
Yeah. It seems that Persistent Storage has been discontinued (e.g. Spaces Persistent Storage Upgrade Not Accessible - #16 by michellehbn). I don’t know if the data inside can be recovered, but you’ll probably need to contact HF: website@huggingface.co