get
https://api.ecartapi.com/api/v2/orders//returns//fulfillments/
Retrieves a specific fulfillment (logistics record) for a return, filtered by its trackingNumber.
orderId, returnId, and id (the returnFulfillmentId / tracking number) are required.
Fallback behavior
If no fulfillment matches the provided id, ecartAPI returns the first available fulfillment for that return. If there are no logistics records yet (e.g. label was just uploaded), the response falls back to the return detail itself.