Was XStore Core plugin activated successfully? Also, make sure that all 3rd party plugins are disabled before the import. Demo content can be imported incorrectly in case a lot of 3rd party plugins were activated on the site before the import.
It is recommended to run import on a fresh WordPress installation. For this you can use WordPress Database Reset plugin https://wordpress.org/plugins/wordpress-database-reset/ The plugin can be used to remove all the existing content and install a new version from scratch.
We will help you with the import. Please provide URL of your site that works, and URL of the desired demo version. Also, we need to know temporary wp-admin and FTP access.
