Hi,
Sorry for the issues you are having.
I took a look at your site and see a script causing the issue.
I am not sure how it got there, but it is not apart of our plugin.
It maybe only happening on Event Pages, because someone placed them in the plugin or a template.
I would try deleting and reinstalling the Events Calendar plugins and checking any custom templates in your theme for the Events Calendar.
I would also read over this article:
http://codex.wordpress.org/FAQ_My_site_was_hacked