This is unfortunate that this has happened and it’s very difficult for us to know who did what.
I will have to reiterate what Will has said earlier: Griefing in PlayCanvas - #3 by will
You should only give somebody write or admin access to your project if you trust them. Don’t just add anybody at random (for example, if somebody you don’t know says they want to help you on your project).
You can back up your projects, either using forking or by downloading your project.
Use version control (checkpoints) to ‘save’ versions of the project that cannot be deleted.
Antisocial behavior on PlayCanvas will not be tolerated. If we can verify somebody has abused another community member in some way, we won’t hesitate to ban that user.
I will repost this as a pinned post tomorrow.