I just went through this with my LA. I contacted Newmar and they sent a Master Key to my nearest dealer. They in turn unlocked my MH. The the cost $18.
You might have the same luck.
Tony & Ruth........... FMCA#F416727
2016 London Aire 4519, Freightliner chassis, Cummins ISX, 2018 Jeep Wrangler Unlimited, Blue Ox Avail with AF1. TST 507 TPMS