Maybe you already have, but Id be on Sam from WPS too, as it looks like he is the guy they talk to there anyway.
In any case, Id call both of them at MS every day. Probably at this point, Id call them both a couple times a day. Believe me, they will get REAL tired of it after a while and get the issue resolved.
You can also try contacting Shinko directly and give them all the same info. They may be able to force something from their end...
In any case, it sucks when people cant have the decency to at least return calls, even if they know nothing more than they did last time. Its worth it to keep their reputation intact to let the customer know what they know or dont know.
Hope you get a resolution, and keep us posted!