We're only hearing her side of the story and she has used a whole bunch of emotive language to make us feel sorry for her which makes me suspicious. It was her choice to sell her book to this publisher. The $20,000 is an advance against future earnings, if she's in breach of contract then there will be no future earnings and she owes the publisher the advance back. There have also been a some famous cases where the book has been turned in and the publisher deems it unpublishable and rescinds the advance. Like the Nanny diaries authors:
http://nymag.com/nymetro/arts/columns/longstory/10330/
The bottom line Publishing is a business, not a charity. A very ruthless business. As an author you're a business person - you should read and understand your contract before you sign it. Pay a suitably qualified lawyer to explain it to you if you don't.
If the story is as she says it is surely her Agent and Lawyer would be making a bigger stink?