She just bought out for the set buyout price. You wanted 2 million for her, and she was willing to give you 2 million. That is unfair, and you should follow your own guidelines.
Jojo, buyout means the highest price someone can pay to automatically win the auction. You should never change it to be higher if someone previously said they'd pay the buyout. It's not kind to treat people like that. Don't do it again.