I got stuck in deep snow. Why didn't the front wheels try to spin?

[Estroil 4.8is]

So yeah I got stuck at the bottom of my driveway. I didn't realize that it was that deep on the way out, but the city trucks plowed us in reall nice. Anyways, I try to reverse and forward, Nothing. So my fiance got out and said that the front wheels weren't spinning at all. Not even a little. Whats up with that! I tried with DSC on and off. I also tried the holding the DSC button until the light went off, it help alittle but not enough. So I ended up digging myself out. I even did a holeshot and the fronts still didn't turn just the rears. Can someone explain how our 4 wheel drive works.