Object Storage Service (OSS) is a low-level service in the sense that, unlike Autodesk Docs or Fusion Team, it does not provide versioning or recycle bin (from where deleted files can be restored) functionality.
If you need file versioning (accessing previous versions of a file), you need to implement that yourself - see https://aps.autodesk.com/blog/file-versioning-buckets
If you need to be able to restore deleted files, you need to implement that too. Either store deleted files in a separate secure bucket that you don't provide your customers direct access to, or just store the deleted files under a different file name in the same bucket that you do not expose to your customers. The latter is simpler because you can quickly and easily copy files around within the same bucket using PUT /copyto/newObjectKey
You must implement protective measures so that buckets and files do not get deleted or their content overwritten by accident, because all OSS operations are irreversible.