I had a similar issue lately with a roll of speaker wire where the buyer claimed it was not as described because it was not as heavy duty as he expected but we clearly had the wire size in the description.

A not as described dispute was opened and I phoned ebay to inform them that it was not in fact incorrectly described and pointed out the details in the description.

The ebay rep agreed with me and they put the case on hold for 10 days for the buyer to return the item, and although the status of the case didn't change in the resolution centre, they treated it as a change of mind return as we have a 14day return policy for such purchases.

They then sent the buyer an email informing them that they had decided that it was a remorse return and that the buyer needed to return the item at his expense for a refund less original postage as per our return policy.

After 10 days had elapsed, the buyer had not bothered to return the item so ebay closed the case and released the funds in paypal.

Admittedly it did take another 2 phone calls to customer service and 2 days after the case had ended before we got the money released but it did happen.

Your case sounds very similar except for the fact that you don't accept change of mind returns, so if you can convince ebay customer service that the item was correctly described they should be able to close the case in your favour there and then.

Remind them that trying to extort funds from you by claiming an item is not correctly described when in fact it was is fraud.