Close observers of Amazon.com noticed something peculiar this week: the company's Canadian site had suddenly revealed the identities of thousands of people who had anonymously posted book reviews on the United States site under signatures like "a reader from New York."

The weeklong glitch, which Amazon fixed after outed reviewers complained, provided a rare glimpse at how writers and readers are wielding the online reviews as a tool to promote or pan a book--when they think no one is watching.

Read more: CNet News.

My sister who is an avid reader and buyer of romance and adventure novels frequently posts reviews at amazon.
Even though she only buys and posts from amazon US someone from amazon canada flamed her for giving a bad review and banned her from ever posting again.
Aside from never buying from amazon again how can she get back?
Thanks.