Solve This Division Problem: DLC Existence Equals Zero

Here’s what’s wrong with The Division in this particular hour: players are reporting that the DLC they just bought is completely missing and undownloadable.
Today would normally have been the release day for Underground, the first gigantic DLC pack Ubisoft has prepared for The Division. You can’t entirely accuse Ubisoft of rushing this one as they delayed the release to make absolutely sure nothing in this pack would discombobulate the game. Confident that they’d sought out and fixed all bugs, they made the DLC available…only to find a bug OUTSIDE of the game that made making this DLC available impossible.
If you buy Underground individually or if you own the Season Pass, it doesn’t matter: the DLC simply will not unlock itself. Ubisoft tweeted, “We are aware of an issue on PC where the Underground DLC will not show as Owned despite owning the Season Pass. This is being worked on.”
In the meantime, they put forth a possible solution for a section of gamers, though they can’t promise it’ll work: if you own the Season Pass on XBox One, attempt to buy the DLC in the store, which will make the game say “Wait, shouldn’t they already have this? OH, RIGHT” and unlock Underground. That’s the theory anyway, and it’ll only work for XBox players. Or you could just wind up giving Ubisoft another $15 and nothing could happen. I wouldn’t take chances.