Attachment with send mail

<?php

$to = 'gnanasekaran.l@innomobileapps.com';
$subject = 'Contact info from Database';
$random_hash = md5(date('r', time()));
$headers = "From: saravanakumar.j@innoppl.com\r\nReply-To: saravanakumar.j@innoppl.com";
$headers .= "\r\nContent-Type: multipart/mixed; boundary=\"PHP-mixed-".$random_hash."\"";
$attachment = chunk_split(base64_encode(file_get_contents('excelfile/contact-info-DB.xls')));
ob_start(); //Turn on output buffering
?>
--PHP-mixed-<?php echo $random_hash; ?>
Content-Type: multipart/alternative; boundary="PHP-alt-<?php echo $random_hash; ?>"

--PHP-alt-<?php echo $random_hash; ?>
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

--PHP-alt-<?php echo $random_hash; ?>
Content-Type: text/html; charset="iso-8859-1"
Content-Transfer-Encoding: 7bit

<h2>Contact Inforamtion from website database</h2>
<p>Attachment below.</p>

--PHP-alt-<?php echo $random_hash; ?>--

--PHP-mixed-<?php echo $random_hash; ?>
Content-Type: application/xls; name="contact-info-DB.xls"
Content-Transfer-Encoding: base64
Content-Disposition: attachment

<?php echo $attachment; ?>
--PHP-mixed-<?php echo $random_hash; ?>--

<?php
//copy current buffer contents into $message variable and delete current output buffer
$message = ob_get_clean();
$mail_sent = @mail( $to, $subject, $message, $headers );
echo $mail_sent ? "Mail sent" : "Mail failed";
?>