Needed: Contact Information- Auburn Hills, MI

Does anyone out here have a contact at Audi's or VW's Headquarters in Auburn Hills, Michigan. My friend and I have both encountered consistently BAD experiences and service with multiple dealerships. Everything from different application of warranty regulations, to how/what is replaced etc. and work being done that wasn't authorized. Being that regional representation is woefully disappointing and dealership representation is dysfunctional at best, we wanted to take the issue(s) to the highest level.
Multiple dealers, three different types of vehicles, a Jetta GLS 2.0, Audi A4 1.8t and an Audi A6.
Any information would be greatly appreciated.
Thanks,