Hi there Steve. My name is*****'m sorry that you're having this issue. It has happened to me before too . Luckily there is a simple fix that works in almost every case. To get them back, go to "manage my kindle" in your amazon account and re-download the book, without first removing it from your kindle device. Also, you can go to https://kindle.amazon.com/your_highlights and sign in with the email address associated with your Kindle to view your highlights.
Please let me know how this works for you. If you need clarification on any of the steps or have additional questions I am happy to assist. I am committed to working with you until the problem is fully resolved.
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