When I get service done, especially in an area I am unfamiliar with, I use www.rvservicereviews.com
to see what others have experienced with a service vendor I am considering. Once my service work is complete I post a report to hopefully help others.
Using this system I have been fortunate in experiencing good service at most locations but in a case like this, where the level of service has not been satisfactory, a posting both warns others and may also prompt the dealer to address the problem.
One of the things that RV Reviews does a little differently is they forward negative reviews to the vendor and offer them an opportunity to respond and/or rectify the problem. This might encourage the vendor to your problem.