I think it's fairly obvious there is a "resistance" element within the SPG GM world. We know they've been playing games in Asia at a variety of properties by designating a couple of rooms as "standard" rooms to avoid awards availability. I know they've also played games at properties I stay at by designating certain rooms as "standard suites" and refusing to upgrade to other rooms. These GM's are employed by franchisees -- not Marriott -- so there are limited options for Marriott but we should out these properties.
That being said, there remains a web-based interface at Marriott.com that pulls from the two databases. The interface and rules from those databases appears to me (as a non-programmer to be --- clunky). For example, if I use a corporate code rather than the same SET code, I get rates on legacy Marriott properties but not SPG properties whereas I get the reverse if I run a SET code.
Further, I've had a run of SPG properties this month including Sheraton, W, Westin, and Luxury Collection. They don't know the new levels and haven't trained. As the W FD person told me, I think we have that information somewhere but I've never seen it. The Luxury Collection FD was very clear ... in a professional Luxury Collection mindset ... that they didn't have that information.
But your situation was handled wrongly and I hope you'll escalate it.