I think it's pretty clear they are fobbing you off. Wax would indeed harden once it cooled, and the volume of liquid you are seeing can't be explained away by a wax coating. Your best course of action is to put your concerns in writing via an email to the dealer, to which, if any repairs need to be done, VWA can be referred. A simple fix now could prevent major damage occurring in the future and I think VWA would be very interested that a dealer is ignoring such an obvious sign of a problem.