Best Amazon Seller Tools – Increase your profits, efficiency, and grow your business with this curated collection of essential tools. Among the many Amazon tools available, Refund Retriever is one of the only tools available that sellers can use to find shipping refunds from UPS and FedEx. They will audit every package you send for late delivery, non-shipment, duplicate charges and incorrect address corrections. Instead of charging you for this service, Refund Retriever takes 50% of any refund credit they find for you.