The refund will go back to the payment method (credit card?) used when you paid. You should have received an email from eBay about the refund and an email from your card issuer if you signed up for online access to your card and receive email alerts from them about refunds, etc. You can also log on to your card account online to look for the refunds. Refunds to cards take up to 30 days depending on your card issuer.
