When testing my contact form, it sends the email, but none of the variables are working. I know very little about php so I was hoping someone could tell me what it wrong with my code.

Below is my HTML code:
<form action="contact.php" method="post" enctype="text/plain" autocomplete="on">
<p> <label for="username" class="iconic user" > Name <span class="required">*</span></label> <input type="text" name="username" id="username" required="required" placeholder="Hi friend, what may I call you?" /> </p>

<p> <label for="usermail" class="iconic mail-alt"> E-mail address <span class="required">*</span></label> <input type="email" name="usermail" id="usermail" placeholder="I promise I hate spam as much as you do!" required="required" /> </p>

<p> <label for="usersite" class="iconic link"> Website </label> <input type="url" name="usersite" id="usersite" placeholder="eg: http://www.travisvalerius.com" /> </p>

<p> <label for="subject" class="iconic quote-alt"> Subject </label> <input type="text" name="subject" id="subject" placeholder="What would you like to talk about?" /> </p>

<p> <label for="message" class="iconic comment"> Message <span class="required">*</span></label> <textarea name="comment" id="comment" placeholder="Don't be shy, leave me a friendly message and I'll answer as soon as possible. " required="required" ></textarea> </p>
<p class="indication"> All fields with a <span class="required">*</span> are required</p>

<input type="submit" value=" ? Send the email!" />

</form>


...and this is my php code at contact.php:
<?php
$name = $_POST['username'];
$email = $_POST['usermail'];
$site = $_POST['usersite'];
$subject = $_POST['subject'];
$message = $_POST['message'];

$mail_to = '[email protected]';
$subject = 'Contact Form...';

$body_message = 'Name: '.$name."\n";
$body_message .= 'E-mail: '.$email."\n";
$body_message .= 'Website: '.$site."\n";
$body_message .= 'Message: '.$message;


$headers = 'From: '.$name."\r\n";
$headers .= 'Reply-To: '.$email."\r\n";

$mail_status = mail($mail_to, $subject, $body_message, $headers);

if ($mail_status) { ?>
<script language="javascript" type="text/javascript">
alert('Thank you for the message. I will contact you shortly!');
window.location = '../index.html';
</script>
<?php
}
else { ?>
<script language="javascript" type="text/javascript">
alert('Message failed. Please, send an email to [email protected]');
window.location = '../index.html';
</script>
<?php
}
?>

If it helps here is the link to the contact form: http://travisvalerius.com/contact/