Logged in to your ZAP-Hosting account you will find the menu item "Contracts & Prepaids" on the left side. There all active servers are listed, but also expired servers that have not been deleted yet.
Difference Between Contracts and Prepaids: Contracts are automatically renewed and must be terminated. Prepaids simply expire after the booked time, as long as they are not extended manually.
All server products for which you selected "Contract" as "Billing type" during the order process will automatically renew unless you cancel them.