The Cloud Poodll system sets an expiry time on files. The default expiry time is 365 days.
Changing the expire time settings
It is possible to set the expiry time to "never expire" so that the files are not removed. This can be done in the settings for the plugin at the admin level. In the case of Cloud Poodll for atto could set the default to never expire, OR you could set it at the time of recording.
Other plugins will have a similar option located on their Admin settings page, and on their instance settings page
Admin default settings
Site administration -> Plugins -> Text Editors -> Atto -> Cloud Poodll
At the time of recording: