I travel Marriott and was surprised two locations recently were out of food for complimentary breakfast with no apologies. Wrote a complaint card to both places and never heard a word. Makes me sad - how can I complain directly to Marriott?
I agree that you should write to the particular manager, but I would also call Marriott at the number on the back of your membership card. I've found that is one of the most effective ways to make your voice heard. ProfChiara