Electrical issue. HELP!!!!

[Chaseurs]

We have a 2021 model 3120RL
Took our trailer to Arizona in early November and stayed in it until the 20th of November. Left it there and went home to Idaho for Thanksgiving. Everything turned off but left it plugged in to 50 amp pedestal. Had friend turn refrigerator on three days ago to electricity. We arrived back in AZ this afternoon. The three Battle Born lithium Batteries completely dead. We also have 600 watts solar panels and 2000 watt inverter. The surge protector indicated “reverse polarity”. I flipped the 50A breaker off, then back on and surge protector said all was good. Also plugged in truck and kept it running. The solar controller came back on line and indicated charge. Batteries indicated 10.8 at that time and were soon at 11.8v. All seemed good. By now we could operate the slides. After about an hour realized we weren’t getting any power to any outlets, and faint beeping from inverter. Wife also turned on hot water heater to electricity. I flipped the 50 amp breaker off, then back on and pedestal power went off. Tried plugging only surge protector into neighbors pedestal. Indicated all ok. Plugged cord in to surge protector and flipped breaker on. Blew that pedestal as well, with nothing turned on in trailer.
Not sure what to try next. Do I dare plugging in to 20 or 30 amp plugs on a third pedestal?
We’re supposed to leave on Saturday to go to the Rose Bowl and I’m frantic.