Billing in your dashboard lists every payment with its date, plan and amount.
A plan bought once runs to its end date and then stops. A plan on automatic renewal is charged again at the start of each cycle, and each charge appears as its own line in the same list.
Cancelling an automatic renewal never takes your access away on the spot. The term you already paid for runs to its last day, and nothing is charged after that.
A plan that ends locks the dashboard, the widget and the API until it is renewed. Your conversations, tickets and WhatsApp sessions stay exactly where they are.