Hello, Maciejk,
Thank you for contacting us and for using XStore.
Please provide URL of your site, temporary wp-admin, and FTP access. We will be able to help you via the child theme.
To provide wp-admin access, you can create a new user account with administrator role via the Dashboard, and provide us with the username and password via the Private Content area.
To create FTP access, please contact your hosting provider for assistance.
Kind Regards,
8theme team