On the support (rather, lack of) from Auto Bavaria, u should write a long complaint letter to BMW in Germany. Notwithstanding that you did not buy from the particular distributor, BMW is a global brand and should be supported by the distributor, regardless where it was purchased from.
Go to the international BMW web site and lodge your complaint there. If there is sufficient numbers of dissatisfied people, I am sure they will act on it eventually. Perhaps someone could draft the said letter and post it here for the benefit of others not so creatively inclined.
In my case, I am a strong believer that AutoBavaria does not give value for money. I prefer my own independent BMW specialist and will stick with him.
Cheers!