I wrote to Atlanta, and send faxes. Faxes never goes to the right place (or may be the right palce is the basket), but letters are sometimes taken into account.
Since one year, I try to write a letter to the person who is commercialy responsible (what does it means ?) in Paris, and I always get beautiful answers, but nothing to compensate. She is helpful when I have problems with Avis, she is OK for correcting miles problems, but never gave me an upgrade, miles, not anything similar.
One day, they sent me a letter to ask me about my adress to send me invitation for VIP events ! How lucky was I !
First a last event I ever participated (I was invite) was the skyteam launch ceremony: Do not laugh : I was invited by... by.... yes, by Air France.
So Atlanta may be an adress to send letters, but my advice would be: send them recommanded, otherwise it is lost.