iPhone kindle app not deleting books

Take a look at this guide:--> https://ebookfriendly.com/kindle-ipad-iphone-ultimate-guide/

If you get no help, contact Amazon Kindle support team and ask for help.

Regards

Giulio

Contact Kindle Support as it's their app.

Yes, that's the right thing to do, when you can't interact with an app.

Giulio