awww, Foodie, I'm sorry this has happened to such a special cake. You did the right thing to freeze it so I can't understand why there is "mold throughout". I, personally, would not try to save it since it's throughout. It's not like you can cut it off.
I don't even try to cut mold off from food. I just toss it. Meanwhile, check your freezer temperature. The mold may have started before you even got it home if the seller didn't store it properly.
My kitchen is for dancing. Bring me sunshine in a cup. ~emily dickinson.