I concur with RogerP. I have had a few items to return in recent months that were not as described and some sellers have actually advised to raise a dispute and let it run its course, as more often than not ebay then provide a return postage label (they send it in an email that say their rules say they don't have to and that the buyer is responsible for returns but for customer relations etc they have decided to). ebay use the collect+ service, so I just stick the label on, get the tracking number, follow the ebay link to enter it and they refund the money (before it actually arrives at the seller).
Heres one of their emails (this was when a car parts sent a completely different set of bulbs to that purchased)
"Good news. We issued you with a full refund of £59.98 on 18 Nov, 2014 that you should receive within 24 hours to the PayPal account you used to purchase the item. The refund includes the purchase price plus original P&P. Please log in to PayPal and view the history page if you don't see it in your PayPal balance. In some cases we are aware that this may take a few days but please note that you will receive an email to notify you that your money has been returned to your account.
We would like to thank you for using the Shipping Label which we provided you with to return the item to your seller. As you may recall from our previous email to you, when an item is returned to a seller we must wait until the item has been successfully delivered to the seller before we can issue a refund. However, as our tracking system shows that you have already sent the item back to the seller and it is with the seller or it will be very shortly, we don't want to delay you getting your refund any longer as you have promptly followed all the necessary steps."
Dave