Here are the steps you may follow if ever you wanted to disable the 'Email Us' function from your website's 'Contact Us' page.
1. Go to Settings > Website Settings > Website Settings
2. Change 'Show Contact Us Form' from 'Yes' to 'No'.
You may change this anytime by reverting it back to 'Yes' should you need the Contact Us Form again form your 'Contacts Us' page.
Have questions? Please feel free to leave a comment or send it via email to firstname.lastname@example.org :)