I assume that you've checked to make sure the cross shaft is still connected to the motor shaft. Is there any noise, like a clicking or snapping? If no noise at all it could be the bevel gear has sheared its drive pin. And of course then you'll have to figure out why. Haven't these legs given you issues in the past, or am I confusing you with someone else.
If you can get the inner leg up enough, you should be able to put the jack under the pad and use it to lift the trailer along with the other leg. That should be enough to get you back on the truck. Then just find level sites and don't unhook the truck. :)