Hi and Welcome. My Name is ***** ***** I look forward to assisting you today with your question.
That is a SCAM virus also called ransomware. DO NOT do anything that message on your Kindle says.
We have to boot your Kindle to Safe Mode and factory reset the device to remove the virus completely. Turn off Kindle. Then press and hold down Volume Down and Power button at the same time for a few seconds and when it turns on, release the Power but keep holding down Volume down and this will boot into Safe Mode.
After booting into Safe Mode, Go to Settings. Tap Device Options, and then tap Reset to Factory Defaults. Tap Reset to confirm. Resetting to factory defaults will erase everything from your Kindle. But after factory reset, you can re-register it with your Amazon account you used on it to redownload all your books/contents without paying again.
Please let me know if that didn't work, so we can continue troubleshooting.Note : This is not my final answer. I strive to provide Excellent service or 5 star service. If you feel you've received anything less or if you are not satisfied or if my solutions didn't work, please don't rate me bad or poor or ok. Instead, please let me know and I will try my best to help you until you are fully satisfied or the issue is resolved.