That first answer is alarming; you should never be compacting your blob store in a restore situation. That takes soft-deleted blobs and permanently deletes them.
Doing an export and re-import of your component database won't cause your blobs to be deleted. It sounds like something went awry and the repositories were somehow deleted, which (if this is done via NXRM will cascade to soft-delete your blobs.)
Have a look at the "Repair - Reconcile component database from blob store" task. It can undelete soft-deleted blobs if they're still referenced in component metadata.