Allow removal of credit card information
Once a credit card has been entered, it should be easy with the UI to remove that information without entering another credit card. At least so if the organization has returned from paid to free plan.
Example: Some developer may have entered their private credit card information to get things going again in the heat of battle. After the stress is over, it should be possible to change back to the free plan (that much is easy) and to remove the credit card information (that one is hard or impossible, given the present UI).