Kindle issue on Iphone

I am unable to delete a downloaded sample book on my Iphone. I tried to go in to the Amazon Kindle content and devices on my PC, however the sample doesn't show as a downloaded book.

This sample book shows in my library ONLY on my Iphone Kindle app. I have long pressed to delete, and remove from library and remove from download, but nothing works to get this book out.

It shows on library and downloads on my Iphone Kindle app, but doesn't appear on Amazon's content.

Unable to delete, it is making me crazy. Any ideas would be great.

Thank you!