Wrong colour item sent

[MyFancyPants]

I won a BIN item on ebay and the seller has sent me the wrong colour, I understand that I contact the seller but what is the normal procedure for returns, do I pay for the return even though the error is not my fault? The listing states that whilst returns are accepted, the return postage must be paid by the seller, is this correct?
Sorry if this is a daft question, but I've never encountered any problems on ebay before!

Politely Tell the seller that since the return is due to their error you expect them to reimburse you for return postage. Otherwise open a case for item not as described.

Most sellers will apologise & sort it quickly for you, give them a chance.