My book has been out of print for a long time but it is still listed for sale on lots of websites. Why?
Even after your book goes out of print, you may still find online bookstores/resellers listing “new and used” copies of your book for sale. You’ll primarily see these on Amazon. These small outfits don’t bother to update their listings when a book is no longer available. They simply take the new book listings from Ingram when a book is released, slap a listing up on Amazon, and leave it there. Of course, if anyone tries to order a copy from them after your book is out of print, they won’t be able to obtain the book and the customer will then receive an email, sometimes weeks later, saying the book is unavailable. While this is a major pain, there are numerous independent booksellers / resellers using Amazon and most of them just don’t care about updating their listings.
If you feel your old publisher might still be selling your out of print book on the sly, try to order a new copy from one of these sellers and see what happens. Don’t send them an instant accusation just because it appears your order went through okay. Like I said above, it could be weeks before they let you know the book isn’t really available.