Handle order cancellations and refunds across channels

Verified steps

1. On DoorDash Marketplace, call the merchant-initiated order cancellation endpoint with the DoorDash order ID and a cancel_reason from the accepted list (ITEM_OUT_OF_STOCK, STORE_CLOSED, KITCHEN_BUSY, or OTHER); note this requires allowlist access from your technical account manager
2. On Uber Eats, call POST /eats/orders/{order_id}/cancel with the order UUID; if the order is already in a terminal state the API returns 404 — handle this gracefully
3. To deny an inbound Uber Eats order before acceptance, use POST /eats/orders/{order_id}/deny_pos_order with a reason code
4. For refunds on Uber Eats, refunds for missing or incorrect items are processed by Uber Eats on behalf of the restaurant; the refund amount is deducted from the restaurant's payout, not processed by the restaurant directly through the API
5. Set up webhook listeners for cancellation events on each platform (e.g., DoorDash's ORDER_CANCELLED webhook) to detect platform-initiated cancellations and update your internal order state accordingly
6. Log all cancellation events with order ID, reason, channel, and timestamp; use this data to identify recurring cancellation causes and address them in operations or menu management