To request a refund for an unused shipping label, return to that order on your Bandcamp Orders page, click Manage Shipping Labels. Locate the label you want refunded from the table of shipping labels associated with the order, and click on the three dots menu, select Request Refund.
Please note: refunds can take up to 4 weeks and will be processed by EasyPost, not Bandcamp. You will have to monitor the state of the refund via your EasyPost billing history as Bandcamp doesn’t have any insight into that process. For the definitive guide on refunds to EasyPost please see the EasyPost help article.