Form send email but it is not always received

[tripodkid]

Greetings everyone!

I don't have much experience with PHP and I hope someone can help me with a form that I'm having problems with. The user accesses the form using a short cut. To prevent them from having to complete fields that don't change some of the fields are completed using the shortcut URL. E.g.

[FONT=Courier New]http://service.my-website.com/index.php?siteName=My_Site&street=123_The_Street&city=My_City&state=SD&zip=12345&tag=Tag1&equipment=Control_Station[/FONT]

To remove the underscores from the form fields I use this code for each field:

<?php
	if (isset($_GET['fieldName'])) {
		$siteName = $_GET['siteName']; 
		$siteNameNS = preg_replace("/[_]/", "&nbsp;", $siteName);
		echo  "value=" . $siteNameNS;
		} else {
		echo "";					
	}
?>

This removes the underscores but seems to prevent the email from being delivered.

Here's my email form:

<?php
//Procees portal.php data into an email

$to = "[e-mail]";

$subject = "Service Request from " . $_POST['siteName'];
$body = "A service request has been recieved from ". $_POST['contactName'] . " at " . $_POST['siteName'] . "\n \n" .
	"Site Name: " . $_POST['siteName'] . "\n \n" . 
	"Street: " . $_POST['street'] . "\n \n" .
	"City: " . $_POST['city'] . "\n \n" .
	"State: " . $_POST['state'] . "\n \n" .
	"Zip Code: " . $_POST['zip'] . "\n \n" .
	"Contact Name: " . $_POST['contactName'] . "\n \n" .
	"Phone Number: ". $_POST['phone'] . "\n \n" .
	"Email: " . $_POST['email'] . "\n \n" .
	"Customer #, Equipment Serial # OR Tag #: " . $_POST['tag'] . "\n \n" .
	"Error Code or Message: " . $_POST['errorCode'] . "\n \n" .
	"Equipment Type: " . $_POST['equipment'] . "\n \n" .
	"Description of the problem: " . "\n" . $_POST['description'] 
	;
$headers = "From: Technical Support <[e-mail]>" . "\n";

mail($to,$subject,$body,$headers);

//Send confirmation email 
$replyTo = $_POST['email'];
$replySubject = "Konica Minolta Service Request";
$replyBody = "Dear ". $_POST['contactName'] . ";" . "\n \n" .
"Thank you for your service request.  A  Specialist will be contacting you as soon as they become available." . "\n \n" .
"Our hours for email response are between  8:00am to 8:00pm Eastern Time Zone,  Monday through Friday. If you have an emergency that requires immediate assistance outside of normal hours please call our call center at 1-800-000-0000 which is available 24 hours a day 7 days a week including holidays."	;

mail($replyTo,$replySubject,$replyBody,$headers);

//Forward to confirmation web page 
header('Location: /confirm.php');   

?>

In all instances the confirmation email is sent and received and the user is sent to the confirm.php webpage. But, when I implement the code which removes any underscores from the form fields the email generated by the form is not received. However, if I disable that code or if I fat finger the information in to the form then the email is received.

Any help resolving this would be awesome and much appreciated!

Thanks!