How to cancel a subscription made by user in the TestFlight?

when we test in app purchase feature in TestFlight, we realize that TestFlight using our real iCloud account in AppStore, but because the app installed from TestFlight, they know it is still "Testing Phase" so they purchase set to FREE.

Now im asking about how to test in app purchase for CANCEL SUBSCRIPTION? I can't found in my real iCloud account, either for my sandbox account inside AppStore settings.

Please any response will helpful. Thankyou.

How to cancel a subscription made by user in the TestFlight?
 
 
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