I would suggest also posting a review on the book's listing page that specifically calls out the problem, probably with a one or two star rating. While I don't condone doing this solely for price considerations the way some do, formatting IS a big deal when it comes to ebooks, and some authors do keep an eye on reviews to let quickly them know when such issues are an obstacle to actually reading the book. It can light a fire under the powers that be to get this stuff fixed. Plus, you'll be letting other prospective buyers know what they're in for--that's not a cheap book, and I'd be incensed if I'd paid that much for something that poorly formatted.
Just be sure to update the review if/when they come through with a corrected version.
