Amazon is known to be a pretty, scumbag corporation in the author community as well.
Just had a similar issue where they erroneously cancelled a promotion for my book, spent months e-mailing me the "we're working on it" message because they didn't want to admit the error, and then when I appealed to the highest level, it got passed off to some asshole in "Executive Customer Relations" who continued to deny, and began to fuck with my account more so because I called him out on his lies.
So yeah, publish your experience with Amazon somewhere visible. In the end, the PR damage they take to their "customer-centic" branding is bigger than the losses you've suffered.