Help!! Why doesn´t this work

[zlehn]

Hi... I have this code... But it does not go to that email adrress when I try to send it, but if I try to send i tto hot mail it works just fine....
Can anybody help and please tell me why thta´s happening...
Thank´s

<?php

$sendTo = "[e-mail]";
$subject = "Mensagem do site da Dinamo";

$headers = "From: " . $POST["firstName"] ." ". $POST["lastname"] . "<" . $POST["email"] .">\r\n";
$headers .= "Reply-To: " . $POST["email"] . "\r\n";
$headers .= "Return-path: " . $_POST["email"];

$message = $_POST["message"];

mail($sendTo, $subject, $message, $headers);

?>