Returns: To process a return request, go to your Manage Returns page, where you can review, authorize, or decline requests. You can also access Manage Returns page by clicking the Orders drop-down menu in Seller Central.
Refunds: A refund should be processed when you have received a return from a buyer, a returned shipment, or have made arrangements to refund a purchase. You can issue refunds in full or in part via the Manage Orders tool. Refer Refund Options page for more information.
Cancellations: If a buyer asks you to cancel an order and you have not yet shipped and confirmed the shipment, you can cancel it in Manage Orders or use an Order Cancellation feed. If you have already confirmed an order as shipped, you can authorize the return request in Manage Returns.
Claims: The Amazon A-to-z Guarantee protects customers when they purchase items sold and fulfilled by you directly. Our guarantee covers the timely delivery, condition, and return experience of items you sell. If customers are unsatisfied with any of the above, and cannot reach a resolution with you, we enable them to file a claim with us. You can refer to the claim eligibility polices on the A-to-z Guarantee page.