Credit:
The statement, from Amazon's Drew Herdener, reads:
These books were added to our catalog using our self-service platform by a third-party who did not have the rights to the books...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....We are changing our systems so that in the future we will not remove books from customers' devices in these circumstances.