Urgente alguien que me pueda ayudar con el formulario que obtuve de una plantillA WEB , estuve modificando los datos pero no me funciona de ninguna manera no se que pueda estar mal ya que no se mucho de programación, cualquier ayuda se los agradecere. 
Código (php) [Seleccionar]
<?php
//Type the receiever's e-mail address
$emailAddress = "info@email.com";
//Type your Site Name
$siteName = "Company Name";
$contact_name = $_POST['name'];
$contact_email = $_POST['email'];
$contact_subject = $_POST['subject'];
$contact_message = $_POST['message'];
if( $contact_name == true ) {
$sender = $contact_email;
$receiver = $emailAddress;
$client_ip = $_SERVER['REMOTE_ADDR'];
$email_body = "The Name Of The Sender: $contact_name \nEmail: $sender \n\nSubject: $contact_subject
\n\nMessage: \n\n$contact_message \n\nIP ADDRESS: $client_ip \n\n$siteName";
$emailAutoReply = "Hi $contact_name, \n\nWe have just received your E-Mail. We will get
in touch in a few days. Thank you! \n\n$siteName ";
$extra = "From: $sender\r\n" . "Reply-To: $sender \r\n" . "X-Mailer: PHP/" . phpversion();
$autoReply = "From: $receiver\r\n" . "Reply-To: $receiver \r\n" . "X-Mailer: PHP/" . phpversion();
mail( $sender, "Auto Reply: $contact_subject", $emailAutoReply, $autoReply );
if( mail( $receiver, "New E-Mail - $contact_subject", $email_body, $extra ) ) {
echo "success=yes";
} else {
echo "success=no";
}
}
?>