MongoDB instances support two billing methods: Subscription and Pay-As-You-Go.
Subscription: Instances paid by yearly or monthly subscriptions cannot be voluntarily deleted or released. When the purchased MongoDB instance expires, it is locked and cannot be read or written. You must renew your subscription to continue using the instance. If the subscription is not renewed, the instance is automatically and irrecoverably deleted 7 days after the end of the service period. Before this happens, back up your data and migrate it from ApsaraDB for MongoDB to avoid data loss.
Pay-As-You-Go: This type of instances can be voluntarily released.
Log on to the MongoDB console.
If the target instance is a replica set instance, you can find it on the Instance List page. Click Release in the work area and click OK in the confirmation box.
If the target instance is a cluster instance, you can find it on the Instance List page. Click Release, and click OK in the confirmation box. See the following figure.