Not that this is the case here since I'd presume the supplier wouldn't put an inexperienced person on a mobile unit, but we've had guys that didn't know how to deal with certain fill valves, especially on our old '85 Pace Arrow with its 80% fill limit. Nowdays there should be no tech that doesn't know how to deal with the valves, but every so often there is. Sometimes I've had to clue them into turning the relief valve knob the right direction. Liquid propane won't go in if the gas pressure above the fluid in the tank is too high. The relief valve has to be open to lower that backpressure.
It's always possible your guage is not sending properly, but after 2 months camping I'm sure your guage is probably correct. I'd either pick up stakes and drive into a station, or ask for a truck with a driver experienced with older RV's.
Been watching the news about the Southwest, Texas, and California getting dumped on. Reckon flashfloods are a threat in that country. The rain is certainly needed in Texas and California, but not all at once. Knock on wood, but Northwest snowbirds could have stayed home this winter and been happy like us... it's been unusual but superb weather. We'll regret it later this summer when the lack of mountain snow affects our water supplies and fire season.
Joel