Try this....remove T stat from wall, unplug telephone-like connector in back for a few seconds, then re-connect. See it that makes it work.
Since you seem to have the RVP T-stat that merges the heat pumps to the LP furnaces and supplements the heat pumps with LP when necessary, and neither of your heat sources work, I would bet the T-stat has lost its mind.
Does the T-stat have a slide switch on the bottom that gives you a gas heat or LP heat selection only? If so, move it to that position and see if the LP furnace/s try to fire up.
If you have a Coleman/RVP T-stat, these folks have technical data for most of that stuff:
Airxcel