I found my books on what apparently is a pirated site:
They have them listed there as free. So it appears that there are devious folks out there that are downloading stuff, copying them and then in some cases are returning them to Amazon. That perhaos accounts for the high rate of returns some are now experiencing. I have only had one return but still it is evident that even with the DRM protection no books are safe once it gets on the internet.
Oh well what to do...If they are pirating blockbusters I guess it is a compliment when they pirate your own work. That is the positiv way of looking at it. I don't approve though.
To find pirate sites that have your book, Google yourself and/or your book's title. About the third or fourth page in you'll see offers for your book from people you never heard of. You can issue cease and desist orders, but even if one site takes your title down another may well pick it up. It's very irritating but shouldn't have much of an impact on your real sales. People who want to read your book will figure out pretty quickly that pirate sites could well be dubbed "viruses R us" or don't exactly have the entire book...
As many have said, don't worry about it. You can't stop it completely. All you can do is attack as and when you see it happening. Copy prevention just gets annoying to some people, and pirates can get around it. Heck, it's even easier with books than it is with movies or music if you can't, you just need to copy it out word for word. Believe me when I say that NOTHING will EVER stop, prevent or even slow down piracy.
Just take solace that the people stealing it are unlikely to pay for it anyway, so it shouldn't count for a lost sale. The people who pirate big blockbuster movies often do so because cinemas charge up to a tenner or more for a ticket, not including concessions, making it a huge rip off when you hear about an actor's salary. But when you can pay a couple of quid for a book to keep for life, many people don't think of it as such a bad thing to pay for the original.
The best thing I can say is to keep writing, promote the heck out of your new book, set a release date and get as many sales on that date as possible before the pirates can get a hold of your book. Then hope that the continuing sales are from honest people.