You can issue refunds at any time via the API or you can look up the charge in your dashboard and issue the refund there. Depending on your customer's bank, he or she will see the refund show up anywhere between 5-10 business days later.
To refund a charge from the dashboard, you can either hover over the charge in the payments overview and click the gray “Refund” link that appears, or go to the specific charge page and click on the gray “Refund” button in the upper right.
Refunds can be whole or partial – that is, you can refund any amount up to the original amount of the charge.
When you refund a charge, the fees you paid to process the charge are also returned to you. That is, after charging and then completely refunding a payment, the net cost is zero. If you partially refund a charge, we refund the pro-rated portion of the percentage cost.
For example, if you refund $50 of a $100 transaction, we refund $1.45 of $3.20. A simple way to think about this is that after charging and then partially refunding a payment, the net cost to you is the same as if you’d charged that amount in the first place.