Did you originally pay using PayPal and if so is your PayPal account still active?

Refunds normally go back to source so that all parties involved are aware of the refund.  

If the original payment method is no longer available then eBay may refund by an alternative method.  They would inform you if that was the case. 

Refunds to buyers

For most purchases, buyers are refunded to their original payment method.

If we're unable to send refunds to the buyer's original payment method, we may provide refunds by another method such as PayPal, or by coupons or vouchers redeemable for purchases on eBay.