@piratis 

Hi,
Please confirm the following information about the reported phenomenon.

  1. Have you inserted an SD card into the camera to store video recordings?
  2. Whether all video recordings stored on the SD card are deleted, or only some of the oldest video recordings?
  3. On the camera's Device Settings > Storage & Recordings > Local Storage page, is the storage empty or full? Is the Loop Recording feature enabled?

Best Regards

  @piratis 

Hi,
It appears that the SD card has been formatted, so all video recordings have been removed. 
Typically, only the person who has your TP-Link account can format the SD card using the Tapo app. If you do not format the SD card in the Tapo app, please confirm whether you have shared your account with others. It's suggested to change the password of your account and enable the 2FA feature to protect your account.
What can I do if I forget my password of the cloud account?
Making Your Account More Secure: Introducing Two-Step Verification (2FA) for the Tapo App
 

Alternatively, if someone removes the SD card from the camera, they can also format it on a PC. Please ensure the camera is placed in a safe location.

Best Regards
 

  @piratis 

Hi,
It's unable to identify the detailed causes based on the information we have. It's recommended to protect your account and camera according to the tips in this post. If the same behavior occurs, we suggest contacting the local support team for further assistance.
Best Regards