One idea is to post as many online reviews as you can -- on every platform that you possibly can. The internet is a powerful tool, and can make or break a business. Enough negative reviews just might make the manufacturer take notice. Who knows.
That being said, I have come to the conclusion that unless someone is spending in the neighborhood of, say, $400,000 or more, the market is full of nothing but poorly assembled low-quality components --- and RVers keep buying them like there's no tomorrow, so the manufacturers have no incentive to change a thing.
Sorry to hear about your problems. Hope they get resolved soon.