By default the backup and delete Jobs are created at startup. It is optional to delete those but we recommend them as things can happen during reboot, problems with disks etc.
The big question is if you had logs from before. If you had there should be a recent file in the backup folder of the installation folder.
If not, you can take your other tape backups, stop the VisualCron service and just copy the items from the "settings" folder of the installation directory over the current. Then start the service.
The reason for why it was deleted is probably in the log file from the day it was restarted. You can send it to
support@visualcron.com. It is called log_serverDATE.txt