The read-only subscription status lets you navigate Cognito-app and see all of the information you and your customers have entered there.
However, any new addition or modification is blocked. If you try to add a new customer, for example, a prohibition message will appear:

The read-only state allows you to:
You can continue read-only, or change your subscription to complete your purchase.
NOTE : After a read-only period of 1 month , we reserve the right to withdraw your subscription, depending on the available resources of our servers.