In case you decide to change back to the free plan, you need to take into account that different platforms have different limitations.
##Create Editor
If you have exceeded Free plan limits, you can still view all your sketches and libraries in Create Editor, but cannot edit them. To unlock editing you have to delete sketches and/or libraries until you get back below the Free plan limits.
##Arduino IoT Cloud
If you have exceeded Free plan limits, you cannot see Things dashboard data or connect your devices to IoT Cloud. To unlock Arduino IoT Cloud features you have to delete the Things and/or Properties exceeding the limits of your plan.
Device Manager
If you have exceeded the Free plan limits for devices/boards, you cannot see device details, control them or connect to cloud. To unlock these features you have to delete boards/devices exceeding the limits of your plan.