Fans pay the tier price, shipping, and a Platform & processing fee. On a US card you get the tier price plus shipping. International cards cost a little more in Stripe fees, so you get slightly less on those.
From the Backers tab you can refund a backer two ways. Your call returns the price and shipping. Not delivered returns everything, fee included. Canceling a funded Encore refunds every backer in full. A refund turns off that backer's downloads and pass.
If a backer disputes a charge, Stripe contacts you and the row shows Disputed. You answer it in your Stripe dashboard.