Trace my subscription cancellation flow end to end and verify it actually stops billing. Follow the cancel button through every layer. Verify and fix: canceling calls the provider's API to cancel the subscription (not just flips a local flag, which leaves the provider billing the customer forever); the provider's cancel webhook is processed so cancellations initiated from the provider's customer portal sync back; the customer keeps access until the end of their paid period (standard expectation) with the exact date shown at cancel time and in a confirmation email; the subscription record reflects the pending cancellation (canceled but active until date X, not simply 'active'); re-subscribing or undoing the cancellation works while the period is still running; and after the period ends, access actually revokes, verified against state, not assumed. Don't make cancellation a dark pattern on purpose (hidden button, retention maze), and equally don't leave it broken in the customer's favor where canceling grants free indefinite access. Don't delete the subscription record. Deliver: the flow trace with each fix, the confirmation email, and verification in test mode: cancel a subscription, confirm access persists to the period end, confirm no next invoice generates, and confirm the provider's subscription state matches my local record.