My products are lost after using Ovic > Import Database > Main Demo

Hi,
Import Demo Data is the process of importing data from our demo to your website. This should only be done when you start installing the website and need demo data to continue editing to suit your needs. Therefore, if your website already has your official data, you should not do this because the data will be changed (overwritten, deleted, conflicted, ...).
If your data (products, posts, pages, ...) has been deleted without any backup, it is definitely not possible to restore it. Try checking the server, hostings to see if there is any backup, please ask for help from your server, hostings manager. We cannot control this issue.
Regards