I have only ever had a free account. My projects are now read only and uneditable. The Project details page says they are public. I have searched the forums but it seems other have had the problem after downgrading from PRO to free. That isn’t the case here.
The projects with more than 5 screens will go in to a read only mode and you would need to remove the extra screens before being able to do any editing on your projects.
With our new pricing and packaging, the free plan includes 3 public projects with a 5 screen limit per project. You can read more about the different plans here.
Please feel free to reach out if you have any further questions!