why this buttons dont work
Please make sure you are using latest version of the theme.
This can be due to plugin conflict on your site so please try temporary deactivating all plugins except Unyson plugin and WpBakery page builder plugins and see whether everything works fine and then enable the plugins one by one to see which plugin is conflicting if any.
and where i can change links?
You can configure it in the theme settings as displayed in the attached screenshot.
Those are the social share buttons so you don’t need to configure any link to make it work.
You can just configure which buttons to display on the site as displayed in the above shared screenshot.
I have tested it on my test site and it’s working fine for me using latest version of Gillion theme.
Please note that the whatsApp button only works in mobile.
If any other button is not working on your site then please make sure that you are using the latest version of the theme and check for plugin conflict as described in the above reply.
I clicked on the facebook icon on your site and saw it is working fine as shown in the attached screenshots.
Does it not work for you?
If not then do you get any error message or anything else?