If you checked all backups you might want to search the disks of the computer(s) you use. Data stored is commonly not really deleted until its overwritten. Maybe some of the lost keys can still be found. Its something I would let an expert do though.
nope, nothing there, i actually do know a bit about data recovery so i have a habit of wiping unused devices clean as i often handle sensitive data
one and only chance is some old backup, but it is quite far away and i'm not to sure if it is from right time...
i will know tomorrow for sure, but my hopes are very low