Sounds like the service manager is covering for the stupidity of his employees and now the owner is covering for him. What the hell ever happened to the customer is always right (which, in this case, he appears to be)?
At least you did the right thing and opened a cased with GM. That's probably what pissed off the dealer.
I wonder if Arnold Chevrolet threatened to sue the 4 people that
filed BBB complaints against them also?