I normally if I can't get anything over the phone. I end up going down to the dealer and then they don't want to piss me off. I start spouting names and what I am going to do. Especially if you have the info, IE Dave's to shove in their face. If the GM of that dealership can't resolve the issue in a more timely matter. Then it's time to jump over their head. It just makes you look stupid to Dave if you did not use the food chain. That is what ALL chain of command is. Better to use it and you get results. If you use it, don't get results, then they can kick the GM to the curb as an example. If you don't use it, and never use the GM, then nothing gets kicked to the curb and you look stupid.
Just my 2cents.