Try this, go into the contact form in the dashboard of wordpress. Go into the Form section then where this is,
<p>Your Email (required)
[email* your-email] </p>
change it to
<p>Your Email (required)
[text* your-email] </p>
ie you just change the email* to text*
Worked for me after spending two weeks trying lots of other more complicated methods that had worked for others