Audi Customer Care Mailing Address?

[mark]

Anyone out there have the Postal Mailing Address for Audi Customer Care
in Auburn Hills, MI? (I May wind up calling them for this information)

It is a very long story but I wish to write to thank a particular Audi
rep. for her pivotal role in negotiating a positive conclusion to my
recent problem with a local Audi dealer.  I have the case # and her name
but not an address at this point.   Any help you could provide would be
greatly appreciated.  Thanks in advance.

BTW: Audi HQ "inspired" the dealer to get their act together.  I was
impressed with HQ's results.

Regards
Mark