Hello,
It might be a cache issue, you can click on cache button from sellacious dashboard. Also, please enable the php executable cli in configuration file according to your operating system.
For backup of Joomla with Sellacious, you can follow this link: https://www.joomla-monster.com/documentation/installation/how-to-backup-joomla-site-using-akeebabackup
Hope this helps,
Thanks