Go to Camping, Campsites and Campgrounds | KOA Campgrounds
and scroll to the bottom. On the left hand side at the bottom of the screen there is a contact us button.
Also you can leave a review of the campground at Reviews of RV Parks and Campgrounds - RV Park Reviews
for other RVers to read.
If you were having issues with a groundskeeper at the KOA you could have reported him to the owners of the park. I know some folks won’t do that because they are concerned that complaining about an employee of a park will cause even more problems.
I hope the dealer fixes the problems you have with your trailer to your satisfaction.