[MarkW83]

Personally I don't think the manner in which you conduct yourself will change the outcome much; BMW will have policies and thresholds in place for when they can and can't give e.g. a goodwill gesture and help out; and I don't think the attitude or manner of the customer would or should alter this - it should surely be dependant only on what has gone wrong, and what needs to be done to sort it out.

I personally only find myself getting angry etc. when I talk to the wrong person in a company, too low down the ladder to actually do anything about my concern. If you get onto the right person as quickly as possible - someone in "authority" who can actually put the issue right - you should find there's no need to be anything other than polite and courteous, while at the same time demonstrating that whatever issue it is, has made you unhappy...

Good luck to those tackling this, hope I'm not the next one...