No you don't. The seller has to make things right with the other buyer but if they sent you an item matching the description of the one you bid in and won it is yours now. Do you want to sell it back to them? If not you don't have to.
Your transaction is complete, and you don't have to do anything. If you are happy with your purchase, do not return it. The seller is wrong to try to make his problem your problem.
depends, do you have a pink anus?
A shop on ebay was selling two razer keyboards which are identical and I was bidding on one and I won it, now I have been using it for like two weeks. But apparently I received the wrong one, but is the same as the one I ordered. The other guy now wants to return his, and the ebay shop asked me to return mine. If the send me the other one too, will I HAVE to return the one I have now?