Contact form on web site does not populate with customers e-mail

We have a customer contact form on our website mercerpublishing.com that allows customers to contact us. The form works fine on my developers test server, but when we download it to inmotion, the email we receive from customers populates with [email protected]

We have no way of contacting the customers who contact us through this form. My developer said there should be some code in the mail.php file on our site that can be fixed to allow this customer service form to work on your servers. Can you look at the code on this file and see if there is a work around or some way to populate the return email with the clients email instead of the default that we are receiving.

Thanks

Brian