I did find the following explanation in the ebay bucks policy document:
5.12 If an Eligible Participant uses the eBay Bucks Certificate towards the purchase of an item that is later refunded, eBay will credit back to the Eligible Participant the Reward amount spent on the refunded item.
Could someone please let me know how I apply for the credit of the ebay bucks?...how does it happen?....does it auto-magically happen when the seller refunds? Thanks