[Ixt]

I've been buying books and decided to return one that I wasn't going to read. There was the "Cancel" option just after the transaction.
I was told that the information about the refund will be available.

I've left the Wi-fi area, got home, synced the Kindle with my Calibre library which is packed with DRM removal plugins so I could switch between the reading devices and I didn't notice the returned book getting transferred to the PC.
After I turned on the Kindle I've noticed that the canceled book was there and removed seconds after only to find out that I have it on my PC.

I am aware that DRM removal is not part of the Amazon's policy but I am not distributing the books to the people.
What happened is that I literally stole the book which I wasn't even planning to read. No one lost anything since distribution of digital books costs little if no money and I got refunded.
Is there a chance that Amazon found out about my action and could terminate my account?
Should I contact them and explain what happened?

Thanks!

EDIT:
Despite the fact I can now read it I think it would be the same thing without the DRM removal if I just transferred the .azw file and returned it back to Kindle. I would still be able to read it on that device.