Sounds like a systemic problem, and from the likely broad non-posting of points, Marriott is benefiting from it significantly. They don't service your room and you don't get your points, so the hotel is saving money.
While the program is currently not worth it to take advantage of forgoing the service for the 500 points, if one does choose then you absolutely should go after it out of principle. Don't let Marriott get away with it since it is likely thousands of people not getting their points.
Send the obligatory email to customer service and hopefully you'll get a reply in 2-3 weeks with the points posting.