Two things I fully understand you being upset, BUT did you take it back to the dealer? (you did not say) and or did you contact the factory? (you did not say) either of these choices are the choices you should be taking, I fully understand you are upset, but it is not the first nor the last time a heating duct was not hooked up or crushed during install.
So before you blame a whole company have it looked at, my cousins 300,000 MH had a number of ducts hooked up from the factory, so it is not unusual for this to happen.
Hope this helps calm down and Happy Camping
2010 Cedar Creek Silverback 35ts
2001 GMC 2500HD w/ Allison & 8.1