Who do I complain to when my complaint is against the general manager of the hotel?
I have always found them very responsive using this link:
marriott on twitter is also always an option, if you partake in the twitter that is.
In addition to contacting Marriott you might check to see if the hotel is owned by a Franchise company and then contact the Franchise Corporate office.
I see where you posted this in another thread and a CM has responded to you. That should be an effective channel.
Let us know how it works out. If you feel comfortable naming the property, that might be helpful for others if your experience might be repeatable.