Hello, Vladis
We need FTP access to be able to connect to your files using FileZilla file manager. Please ask your hosting provider support to create FTP account to your site files and give us the credentials (hostname, username, password, port).
As we can see it is not our theme activated and there is no Core plugin.
After getting FTP access, activate XStore theme, disable all 3rd party plugins, and activate XStore Core plugin then.
Let us know in case you face a problem or record a video of the problem, please.
Kind Regards,
8theme team