Email information including any errors are stored in the session, so you can try adding this to the bottom of the page:
<?php var_dump($_SESSION); ?>
That will have more information on any errors the page might have. It could be an error sending the email, or spam blocking preventing its delivery. Either way the error message from the above code will shed light on it. Once it has been added I can look at the page again and give more advice based on what is there.