Hello, @Tal,
1. I have debugged your site now and found the cause of the issue, Actually, the filter is working fine on your site but it has been hidden on your site using the hidden class and that might be because of any third-party plugin conflict.
Please check your site screenshot: https://postimg.cc/gxh00yNh
And I have tested the same filter on my test site and it is working perfectly fine for me without any hidden class: https://postimg.cc/H8JghHNM
That is the main issue, so you have to try to disable all the third-party plugins (including cache plugins), that does not come bundled with XStore https://xstore.helpscoutdocs.com/article/36-included-plugins , clear the cache of the browser, and check then. Maybe one of the additional plugins is a reason for the problem.
If the issue still persists then please keep the plugins disabled and let us know I will debug in deep to find the cause of the issue and also your permission to debug your site which includes deactivating all the third-party plugins and on-site Customziation as well.
Note: Please take a complete backup of your site first, before going to disabling the plugins to avoid any inconvenience.
2. Your issue has been solved, I have set the Shop/Category page layout as a sidebar from XStore >> Theme Settings >> WooCommerce >> Shop >> Shop Page Layout: https://postimg.cc/rDhLMDL4 and then set the Filter from Appearance >> Widgets >> Shop SIdebar: https://postimg.cc/kBTnX1QD so now it is showing the sub-categories on your site in the sidebar: https://postimg.cc/wR3w5jGC
3. Try to disable all the third-party plugins (including cache plugins), that does not come bundled with XStore https://xstore.helpscoutdocs.com/article/36-included-plugins , clear the cache of the browser, and check then. Maybe one of the additional plugins is a reason for the problem.
If the issue still persists then please keep the plugins disabled and let us know I will debug in deep to find the cause of the issue and also your permission to debug your site which includes deactivating all the third-party plugins and on-site Customziation as well.
Note: Please take a complete backup of your site first, before going to disabling the plugins to avoid any inconvenience.
Regards 8Themes Team.