Whenever comments appear in the Disqus admin but not on the relevant page on your site, this means there are actually two unique discussion threads in Disqus. One thread (with 0 comments) appears on your site, the other thread (with all missing comments) appears in the admin.
Most often this results after changing either your website's URL configuration or the Disqus configuration on your site. For example, this can happen after:
Moving domains, e.g., http://examplesite.blogspot.com to http://examplesite.com
Changing permalink structures, e.g., http://examplesite.com/sample-page.html to http://examplesite.com/sample-page/
Changing permalink styles such as camel-style slugs to all-lowercase slugs, e.g., http://examplesite.com/Sample-Page.html to http://examplesite.com/sample-page.html
To fix this issue, merge the affected threads using one of our migration tools.