I have had my Gorgonzola in the maturing box for 10 days turning each day it is shiny on the outside, hard and does not have any mould.
When I have had my cheese turn out as you described it was because it dried too much. One time was because I pressed it until it became like leather (oops). The other time it just wasn't covered well enough and the drying was only on the surface.
The lack of mold on your Gorgonzola could also imply that it was too dry- however that mold does require fairly specific temperature to grow well so that isn't conclusive either.