I do not see your site URL.
You can find 1.0.23 version of Core plugin on this page – https://www.8theme.com/downloads/
If this is a new installation, it would be better to use the latest theme version (5.1.3) and Core plugin – 1.1.7. We’ve sent theme archive to your registration email. After uploading the latest version of the theme, try to import the demo one more time.
If this doesn’t help, please provide us with your site URL and temporary FTP access.
