Thank you for your post. I am sorry for any inconvenience!
First, I would double check to make sure you're selecting the correct book from the drop down. There are entries in the drop-down which can appear to be the same title.
Next, you could try loading the page in a private browsing window. (instructions here: How to Enable Private Browsing on Any Web Browser ). Doing so will give you a different question to answer.
If that doesn't help, please reply with the ISBN of your book and I will work on getting you a code.
Please let me know if you have any questions. Have a great day!