Yes, you got scammed. You were sold a returned product that was replaced. Sellers on sites like eBay are not authorized Apple resellers. You have no idea where that seller got those AirPods. They were certainly NOT obtained from Apple directly. Think about it, if they were from Apple the seller could not possibly have paid wholesale since they are not authorized resellers. If you got a fantastic price then how was the seller able to do that.
There a a number of scenarios of how that seller got those AirPods. They could have gotten them from an individual who got a replacement but failed to send the ones you bought back. They could be stolen, etc.
If that seller has a 98.7% satisfaction rating then they should be more than willing to take them back and refund your money. If they refuse that proves the scam. The eBay seller could have ben scammed themselves.