It happened due to alleged copyright infringement in July 2009
On Friday, it was “1984” and another Orwell book, “Animal Farm,” that were dropped down the memory hole — by Amazon.com.
In a move that angered customers and generated waves of online pique, Amazon remotely deleted some digital editions of the books from the Kindle devices of readers who had bought them.
An Amazon spokesman, Drew Herdener, said in an e-mail message that the books were added to the Kindle store by a company that did not have rights to them, using a self-service function. “When we were notified of this by the rights holder, we removed the illegal copies from our systems and from customers’ devices, and refunded customers,” he said.
—Amazon Erases Orwell Books From Kindle
Note that they removed only a particular set of those books, so the book remained available in the stores and on many Kindles. The claim doesn't imply otherwise but it needs to be read carefully.