on the contact us page, you have a form, the action of the form is set to post to the Contact_OK.asp, You have applied the Universal Email Behavior to the contact.asp page, you need to apply it to the forms action page:Contact_OK.asp
<form action="Contact_OK.asp" method="post" name="Opmerking_Vraag" id="Opmerking_Vraag" onsubmit="MM_validateForm('Naam','','R','Email','','RisEmail','Onderwerp','','R','VraagOpmerking','','R');return document.MM_returnValue">