ecc-customer-billing-ops

First confirm the duplicate by listing the customer's active subscriptions in Stripe. Cancel the extra subscription, refund only the duplicate charge, keep the intended subscription active, and document the reason before sending a follow-up message.

Classify the case before refunding: accidental duplicate purchase, failed checkout, missing self-serve controls, or genuine product failure. Refund only the affected charge after classification, and log any product issue separately for the backlog.

Prefer the hosted Stripe billing portal whenever it already provides the needed controls, such as cancellation, payment method updates, and invoice access. Build custom account-management code only when the portal cannot cover the workflow.

Start from the strongest identifier available: customer email, Stripe customer ID, subscription ID, or invoice ID. Support emails or GitHub usernames can be used only when they are known to map back to billing records.

Annual plans, team plans, and prorated states require verifying the contract shape before any action. Refunds should never be issued blindly, and secret keys, full card details, or unnecessary customer PII must never appear in responses.