Something to try (You probably already know):
Post your comment with a specific book title(s) in the Kindle discussion forum on Amazon. I did that when Sue Grisham's new book showed up as costing as much as the hard back edition. Within hours the price came down, but not to 9.99. Others jumped on the discussion and suddenly the book was priced at 9.99. I think that someone from Amazon is monitoring the discussions and "reviews". Maybe it will help bring the problem to light. Also, write the customer support--just in case.