Web Form Generating 2 E-Mails

[Dankees]

I have a new web form that I am testing, and I am getting two e-mails every time the form is submitted. Can someone please take a look at my PHP code to see if there's something in there that's causing the double e-mail? Thank you.

<?php
if(!isset($_POST['submit']))
{
    //This page should not be accessed directly. Need to submit the form.
    echo "error; you need to submit the form!";
}
$firstname = $_POST['firstname'];
$lastname = $_POST['lastname'];
$visitor_email = $_POST['visitor_email'];
$phone = $_POST['phone'];
$emailcheckbox = $_POST['emailcheckbox'];
$phonecheckbox = $_POST['phonecheckbox'];
$fafsacheckbox = $_POST['fafsacheckbox'];
$cssprofilecheckbox = $_POST['cssprofilecheckbox'];
$verificationcheckbox = $_POST['verificationcheckbox'];
$tapcheckbox = $_POST['tapcheckbox'];
$loanassistancecheckbox = $_POST['loanassistancecheckbox'];
$consultationcheckbox = $_POST['consultationcheckbox'];
$nassau = $_POST['nassau'];
$suffolk = $_POST['suffolk'];
$borough = $_POST['borough'];
$learn = $_POST['learn'];
$comments = $_POST['comments'];

//Validate first
if(empty($firstname)||empty($visitor_email)) 
{
    echo "Name and e-mail address are mandatory!";
    exit;
}

if(IsInjected($visitor_email))
{
    echo "Bad email value!";
    exit;
}

$email_from = 'Contact@FinancialAidFiler.com';//<== update the email address
$email_subject = "FinancialAidFiler.com E-Mail Inquiry";
$email_body = "Name: $firstname $lastname.\n".
$email_visitor_email = "E-Mail: $visitor_email.\n".
$email_phone = "Phone Number: $phone.\n".
$email_emailcheckbox = "Contact Preference: $emailcheckbox\n".
$email_phonecheckbox = "Contact Preference: $phonecheckbox.\n".
$email_fafsacheckbox = "Interested In: $fafsacheckbox.\n".
$email_cssprofilecheckbox = "Interested In: $cssprofilecheckbox.\n".
$email_verificationcheckbox = "Interested In: $verificationcheckbox.\n".
$email_tapcheckbox = "Interested In: $tapcheckbox.\n".
$email_loanassistancecheckbox = "Interested In: $loanassistancecheckbox.\n".
$email_consultationcheckbox = "Interested In: $consultationcheckbox.\n".
$email_nassau = "Nassau County: $nassau.\n".
$email_suffolk = "Suffolk County: $suffolk.\n".
$email_borough = "Borough: $borough.\n".
$email_learn = "How Did You Learn About Us?: $learn.\n".

"Comments:\n $comments".
        
$to = "Contact@FinancialAidFiler.com";//<== update the email address
$headers = "From: $email_from \r\n";
$headers .= "Reply-To: $visitor_email \r\n";
//Send the email!
mail($to,$email_subject,$email_body,$headers,$town);
//done. redirect to ThankYou page.
header('Location: ThankYou.html');


// Function to validate against any email injection attempts
function IsInjected($str)
{
  $injections = array('(\n+)',
              '(\r+)',
              '(\t+)',
              '(%0A+)',
              '(%0D+)',
              '(%08+)',
              '(%09+)'
              );
  $inject = join('|', $injections);
  $inject = "/$inject/i";
  if(preg_match($inject,$str))
    {
    return true;
  }
  else
    {
    return false;
  }
}
   
?>

Actually, I am getting three e-mails.

The form is located here: http://www.financialaidfiler.com/Form/Form-Page.html