Had a buddy with a leaking toilet on his first trip, took it back to the dealer, and they told him it would take a month to fix it. So he started walking around the new campers and talking to people looking at campers and told them about the issues with his new camper and how they were taking forever to fix it. about the time he got to the 2nd family the service guy came up and told him it his camper would be fixed in 15 minutes.
You've got to get them where it is painful. It takes not time to reply to an email, but when you start costing them sales and making them look bad, it gets their attention. Although the way campers are selling now, it may not affect them.