$headers = 'MIME-Version: 1.0\nContent-type: text/html; charset=iso-8859-9\n';

$mail->Body ="İSİM : " .$_POST['isim']."\n"."\n";
$mail->Body .="E-POSTA : " .$_POST['eposta']."\n"."\n";
$mail->Body .="TELEFON : " .$_POST['telefon']."\n"."\n";
$mail->Body .="MESAJ : " .$_POST['mesaj']."\n"."\n";