AMBC – Association of Mail and Business Centers blog post

These GSR (guaranteed service refund) late package refunds are only provided upon request, you NEVER get them automatically. UPS & FedEx offer a great money-back guarantee policy on late deliveries, however, they don’t necessarily make it easy to get these refunds.

Refund Retriever automatically audits your FedEx and UPS invoices each week to find these packages and have the credits placed back on your invoices. We get paid paid after the carrier credits you and if you are 100% satisfied with our service. If there are no refund credits, you owe us nothing! There are no setup, monthly, or cancellation fees