Hello sellaholic.2012 (tumfighting23@gmail.com),
Thank you for emailing us wanting to know more about when your buyer receives the wrong item. We do hold the seller responsible for the return shipping charges when your buyer receives an item they never bought but instead, they receive something completely different. In regards to your question about when you pay for return shipping, when your buyers select the return reason: Differ From Listing, Defective Item, Arrived Damaged etc we then consider that an Item Not As Described and for which those reasons we hold the seller accountable for the shipping charges.
I hope I cleared up any confusion, if not or you have more questions feel free to contact us here at eBay.
Thanks,
eBay