Kris,
Your last post about the white wire being positive voltage seemed unlikely. RED is generally used for positive. I'd suggest you unplug from shore power and disconnect the batteries. Then use a volt-ohm meter to verify which wire is really supposed to be hot. One of those wires from the battery goes to the circuit breaker buss bar. The breakers have a copper buss bar that conducts voltage to all the breakers. The battery connection is to that copper buss bar. That's the positive/hot wire from the battery.
Use your battery charger to recharge the batteries out of the RV.
Use the 12V guide I linked to in post #4 to diagnose the problem.
If you actually reversed polarity yesterday, you may have blown the power converter fuses.
If you don't have a volt-ohm meter, it's going to be very hard to figure out what's wrong. You might need to get local help.
Btw, batteries don't usually do well after being completely discharged. Hopefully yours will still work well.