It turns out you can get refund, I got it by emailing Customer Support -> Purchases, Billing & Redemption

I don't own IPad or IPhone and I bought this on iTunes thinking I could read it on my Mac. It turns out I can't, and they don't provide refunds.

Purchase complete. Your name, and David's, is enough for me. Even in the impossibly unlikely event that it had nothing of value, it's the least I could do to thank you for what I've learned from both of you since switching to the Mac. Congratulations on the project and thanks again for your efforts.

Well this is exciting! Downloading now, can't wait to dig in.