Many changes cannot be made to existing data feeds while there are live subscribers. These include updates to list prices and applied discounts for specific customers. This limitation has been put in place to protect the customers from unexpected changes. In order to make changes, you will need all customers to unsubscribe from these data feeds. You can ask customers to be more proactive and unsubscribe on their own, or you can revoke access to these data feeds for all of these customers by following the process outlined in this help article. Once all customers have unsubscribed, you can delete and edit the data feeds.