If you've tried to purchase my 'Secret Circus of Pain and Degradation' from Pink Flamingo's website in the last couple of days you'll have found it shows as 'product not available'. You may have found similar problems with other ebooks from other publishers as well.
This is because major credit card companies have decided to withdraw services from 'adult' websites offering content that includes or depicts coercion and nonconsensual activity. Since the 'Secret Circus' book opens with a description of an abduction, it's one of the many products Pink Flamingo have had to remove from their site.
Third party sellers remain unaffected, so the book is available from Amazon Kindle and AdultEbookShop, and apparently also in Nook format from Barnes and Noble.
Meanwhile, Pink Flamingo have plans in motion for the continued marketing of titles they've had to remove; these include a separate web outlet outside the US, since this is a US domestic policy, and further third party sales through non-US sites such as BDSM-Books.com. Excerpts from books will be taken over to their free story site, which will be revamped for this purpose: http://www.freeeroticstoriessite.com.
Finally, the print version remains available - but contact Pink Flamingo directly and be prepared to pay with a check (or cheque), or money order.
Pink Flamingo comment: "This is obviously a significant change in our business. It’s not the first time that there has been a conservative backlash against this industry; we’ve weathered several in our 17 years ... While the credit card companies have every right to deny their services for purchasing certain products, we consider this a free speech issue and a form of censorship."
If you're a member of Fetlife you can see a more detailed discussion of the credit card changes and the way they're affecting the adult ebook market as a whole in "The Kinky Intellectual's Book Club" discussion group.