If your messages of assurance will not work that the item is real, and the buyer opens a case for item not as described, this is all automatic, no human contact, you will have to accept, and refund the buyer.
Accept the case within 3 days and in that time provide a paid for tracked postage label.
Only on receipt of your item do you fully refund, within those case details. Do so within 48 hours.
Stick within those timeframes, and your seller fees will be refunded and your seller performance not affected.
If a different pair is sent back you can appeal the decision of the refund, send in evidence such as photos of the missing logo on the pair received, and the logo on the one sent out, any other differences.
If you need to, this explains how to appeal the decision for the refund.
https://www.ebay.co.uk/help/selling/manging-returns-refunds/appeal-eBays-decision-return-missing-ite...
@jbarnham
