It's disappointing that you are having such an experience with your Air. Although I was not happy at all with the chain of events, I was kept in constant contact and after the service tech got into an accident with the car, the service manager stepped in and called me several times a week and kept me informed of everything.
I would recommend that you find out who your service manager is (not the service tech or service advisor) and speak to him/her directly. Lack of communications is unacceptable. Also, call customer care and demand that they have the service manager call you.
Lastly, I would like to say that this type of issue that has plagued me and others (turtle mode) is a very complex issue to diagnose since it can be many different causes to this mode. They engineers have to review a ton of data to get to the root cause and this takes time.