Well as much as i would also like to think people don't screw others over, it's happened to me toooo many times, so i don't take risks anymore.
I would immediately take this to the BOI, because the longer you wait, the harder it gets for you to get your money back. I would copy and paste all emails and photos you've ever took and send the link to the seller.
This is NOT NOT NOT an oversight, that is a pretty nasty kink and you wouldn't ever find me dead breeding her, i don't want to create more offspring with kinks. This is a serious matter and the seller needs to own up to it. Granted it's the holidays, but everyone can take 5 minutes to answer an email, so it does sound like he is avoiding you.
Like I said, get your post made up and post a thread in the BOI to get the ball rolling.