There's not a Mythic Chat up right now, but the gizmo is functioning fine. You might have turned off chat by accident, in which case there would be a red circle in the bottom-right of the screen. Otherwise, try refreshing the page, logging out-and-in, or seeing if your browser has any distortions that might be covering up the bottom.
Assuming you've done all that, maybe it's a cookie/cache thing? You could try clearing your cache, that's sometimes a good step.
I tried to turn on my chat when saw this topic and it disappeared. Doing a hard refresh with a clear cache (ctrl+r, ctrl+F5) didn't work, but deleting the cookies solved the issue.