I did a quick scan in your head, there are a few errors that aappear to be added by the plugin you are using. You may be better off using a different extension or doing some work in the plugin php files from the plugin.
But so far, I noticed it re-wrote your head declarations as such
<style charset="utf-8" type=\"text/css"\>
I cleaned a few out in the inspector. But the mess is huge. I think youa re better off using a different contact form extension or using the contact module that comes with Joomla to create the form