Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
Whenever I try to purchase an epub using credits, I get this message "The BookCopy instance is not valid. Details: volumeId is not unique (value: 590041a1532c2fd11991dbca)."
BookCopy
volumeId
Hmm, never seen this issue before. You're better off sending an email to @support for a faster assistance.