The way I do it:
Tilt fridge a bit, so it will stand only on one side of styrofoam.
Kick "free" side of styrofoam, to break it out and kick out from under the fridge.
Tilt the fridge to the other side.
Kick second half of styrofoam.
WARNING You need to be big and strong enough to be sure you can actually hold it when you kick your styrofoam. Tilting too much, kicking too strong or holding too weakly may lead to damaged equipment and to injury.
This is just obligatory warning, the fact I had no problems in the past does not mean it is safe for all. I'm tall and heavy. But it worked for me like a charm.
If you have a friend to help you, one of you should tilt the fridge, and other should break and pull away styrofoam. Much safer that way.