private function sendReturnReceipt()
{
$mail = new Mailing();
$mail->setMailTo($this->email);
$mail->setSubject(PAYPALRECEIPTSUBJECT);
$body = PAYPALRECEIPTBODY;
$body = str_replace("<time>", $this->transactionTime, $body);
$body = str_replace("<id>", $this->transactionID, $body);
$body = str_replace("<amount>", $this->amount, $body);
$mail->setBody($body);
$mail->send();
}