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I bought the so-called "Adventure Pack," which includes "Dance of Death" and "Pirates." It didn't work with my old Uplay account, which already has the heroes (purchased on Uplay) that I've already completed. Technical support just shrugged it off, saying it's not their problem, and I should pay attention to what I'm buying.
In the end, I gave up on Uplay, bought the full version on Steam. I don't care about the platinum rank anymore.
If anyone has an old, bare-bones Heroes version without any expansions, I'll give away what I bought here:
http://www.plati.ru/asp/pay.asp?idd=1386552
Write to me in a private message.