must be buy it now on auction sites not auction to get distance selling rules. if faulty or not as described seller pays or refunds return postage (problem is eBay isn't geared towards this like amazon is). you should only be out of pocket for time and packing it. if you don't like it then you pay return postage,but should get full refund including original postage.
contact paypal, they may help. failing that credit / debit card company and head towards the chargeback route.
I assume you accepted the refund offer? if you did, best not to if you are not happy, else dispute is still open?