------ Solution ------ The issue was on our server. It can only handle post requests if we put www in front of our domain name. So that\'s what
Have you tried reading the raw post data in PHP? Something like
$data = $xml = file_get_contents('php://input');
Have a look at this link for more info
http://www.codediesel.com/php/reading-raw-post-data-in-php/