Oh no! Thank you for letting us know. While we make sure that your security is our top priority by adding multiple layers of protection, we encourage you to change your account password and check your two-step verification settings to prevent this from happening. Here's how: Add 2-step verification to your account on the Nest app.
If your video history got deleted it will be deleted from your cloud storage as well. There’s no guarantee that it can be retrieved but let’s give these steps a try:
The time it takes to download your Nest data would depend on the file size. Once the download is complete you'll receive an email notification.
Let me know how it goes.