You need to deactivate it from the setting.
De-activating the plugin will not stop it from loading cache content.
Please see screenshot of your website source code.
This is what I saw at the end of your page source.
<!– Dynamic page generated in 1.830 seconds. –>
<!– Cached page generated by WP-Super-Cache on 2016-06-14 22:37:22 –>
<!– super cache –>
I only write what I saw, I don’t make wild guesses.
Enter your Custom CSS and clear your cache content.