Data of all the subscribers of your plans are listed on your ExplaraBiz Dashboard under Customers/Subscribers.
Search for the subscriber whose plan is to be cancelled. Find the subscriber, click on the Edit icon, and set the status as "Cancel." Once set, click the Update button at the bottom, and now the system will take care of cancelling recurring billing for the selected customer.
Note: Once the status is set to "Cancel," the subscriber would not be billed after that.