How can I void a label that a customer did not use?

Efficiently void unused prepaid shipping labels with Rich Commerce's guide. Learn how to initiate refunds and prevent billing for canceled or incorrect labels.
Shippo automatically voids and refunds unused labels after 30 days for their USPS-master account and selected other accounts. See here for details
ShipStation requires to manually void labels inside the ShipStation dashboard within 28 days for their account. See here for details
Shipping labels created through EasyPost are generally eligible for a refund before the label has been used to ship a package with the carrier. Refunds can be requested on the EasyPost dashboard Shipments Page, but they can also be refunded via the API Shipment Refunds method as documented in their API Documentation. In order to refund a shipment, follow the steps outlined in the following article: