Audible book refund

Good day

I purchased a Narnia Audiobook ("The Chronicles of Narnia" for £25.99) using iTunes (on my iPad), but it would not download. It said

"You have already purchased part of this item but it has not been downloaded yet."

I have searched everywhere (iBooks, my iPhone, iTunes on my Macbook) for this content and tried everything I know to download it, but nothing worked so I would just like to cancel the transaction.

I do not even see it under my recent purchases at https://reportaproblem.apple.com/, so I'm not sure what the issue is. I just don't want the money coming off at some later stage.

Many thanks

Justin Lawrence

UK