Returns - sent wrong item back

[roan1153.evxneis44]

Buyer bought item then 4 weeks later wanted a return, within policy I had to accept. Purchase was a game, used, which is annoying as it means they likely played it and decided to get there money back, claiming it was defective. 

So they sent the game back, but its not the game I sent them. Obviously I can't refund, but here's the issue, it is the same title just not the one I sent. The one I got returned is brand new and sealed which is strange as I sent a used/very good copy to the buyer. 

So am a bit confused to be honest, they have marked it defective, meaning the copy they sent me is, but this isn't the one I sent then.

Any advise 

[redwick1]

Ebay almost always go with the buyer so now you have an item back you will have to refund within 2 days

If you dont then ebay will force it and you get a defect and pay the fees

Does seem a bit odd to have a brand new item returned instead of a used one.