標準スニペットのContactFormから送ったメールが文字化けしてしまいます。

$from= '';
$address='';
$from_email= '';
$message= '';

$postSend= isset($_POST['send'])? $_POST['send']: 'false';
if ($postSend == 'true') { 
    $to = ($recipient_type=="static") ? $static_recipient : $_POST['to'];
    $from = $_POST['name'];
    $address = $_POST['address'];
    $from_email = $_POST['email'];
    $the_subject = ($subject_type=="static") ? "$static_subject" : $_POST['subject'];
    $message = $_POST['message'];
    if ( ($from == '')||($address == '')||($from_email == '')||($message == '') ) {
        $SendMail .= "<p class=\"$failClass\">$emptyFields</p>";
    } elseif (eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $from_email)) {
        $subject = $the_subject;
        //$headers = "From: $from <$from_email>\r\n";
        $headers = "From: ".mb_encode_mimeheader($from)."<$from_email>\r\n";
        
        // clean out potential tomfoolery...
        $message = $modx->stripTags($message);
        
        $body = "Name: $from\nAddress: $address\nEmail: $from_email\nMessage:\n\n" . $message;
        if (mb_send_mail($to, $subject, $body, $headers)) {
            $SendMail .= "<p class=\"$successClass\">$success</p>";
            $SendMail .= ($debug) ? "<p>$to\n$headers\n$subject\n$body</p>" : '';
            $from="";
            $address="";
            $from_email="";
            $message="";
        } else {
            $SendMail .= "<p class='$failClass'>$generalFail</p>";
            $send = "false";
        }
    } else {
        $SendMail .= "<p class=\"$failClass\">$emailFail</p>";
        $send = "false";
    } 
} else {
    $SendMail .= "<p>$instructions</p>";
}