Yeah, I'd say it is time to send that back and re group here. Well, you know a hell of a lot more about what won't work now.
Maybe it's time to design your own. Here's some food for thought. How about a set that doesn't fold but has a quick attach/remove design? Still free from the ground by approx. 7" and a 7/7 or 7/10 rise/run Starting at floor to 1st step down.
I'll give it some thought. How are your fabricating skills? Or do you have a metal guy? Can you give me a pretty close dimension From top of finish floor to bottom of frame rail and a sketch of the frame at the door area. I am familiar with that tongue frame that comes back there.
McDave