It sounds to me like either a mistake on the website (their problem and not yours) or call center staff not being aware of what is on the website (probably).

I would keep a record of the person's name and the conversation you had so you have proof of calling within the 24hour window.

Does Aeroflot have any local or airport offices in the US (run by them rather than a handling agent). I would try to track down their number. They might be more aware of local policies.

Good luck and let us know how it works out.