Hi,
From what I understand the developer of the Facebook comments plugin has already discontinued the development of the plugin.  
If I go to the comment section of a blog post it still asks me whether I want to make a default comment or Facebook comment.  When I click Facebook comment it will come out with the shortcode [fbcomments].  Can you please update the theme to remove the plugin and that functionality for comments in the theme.  
I can email you a screenshot if you want as I can’t figure out how to attach a photo here.
Thanks.