I don't have any advice on the best process to use to file a complaint in this situation; however, I do have an observation. You should have filed your complaint immediately. The Marriott FT Lurkers would have been a good place to start. By waiting a couple of weeks to complain, it will have lost a lot of the potency. E.g. if the issue was that bad, why did you wait to complain? Regardless, good luck and hope your complaint is resolved satisfactorily.

--Jon