God's Dad. Do I understand this correct that the pulisher is now actually selling your book? I'm not a big FB-er, but can someone sell via FB in the same way as you would via an online shop with a buy now button?
The following is just a thought, but if they are actively selling it (posting it out, or via downloads), you might want to check where you stand with self-publishing. I have no clue whatsoever about the legallities of such things (I'm a newbe), but if the publisher is selling your book via FB or other means, it might get you in 'troube' if you self-publish and get your own sales. It might prevent you from self-publishing. So please check that. I'd hate for you to have more hassle. I suggest you ask someone for advice on where you stand, not just on this detail, but on the whole entire matter. Are you a member of the Society of Authors? If not maybe join them. They may have a legal team.
I'm really sorry to hear about your experience. It's horrible. By the sounds of it, you've worked so hard. You don't deserve this.
Also, once all this is settled, maybe let the forum know who it was so we can all be watchful. (Not sure about the legalities of this matter either.)
In the meantime: keep your spirit up. Don't let it derail you, and don't lose heart. Keep writing, and keep the vision of book sales firmly in front of your eyes. You'll get there!