The 'Start a Conversation' button on our Support page allows you to access a live chat, and get through to an agent if our bot doesn't resolve your issue first. It looks like this on desktop browsers, but you can also access it from mobile (though it will be laid out slightly differently):
For most, the button should fully load and be clickable within a second or two.
If it won't load, it could be that your browser's adblockers, or similar applications, are interfering with our back-end. Try disabling them for the Support page. If all else fails, try using a different browser.
See also: How to contact MetaMask Support