eBay do not see the item, so that is not how it works I'm afraid.
If the buyer opens a case for item not as described, then it's all automatic and no human contact. You will need to accept the case and refund within 3 days, if you want your item back first you pay for that tracked return postage, and only refund when the item is back with you. You'll have 48 hours to do so.
Stick within those timelines and your seller performance is not affected.
If either you or the buyer ask eBay to step in, if the case is escalated for the refund you can then appeal that decision. The link below explains how. I won't admit it's easy, as said, eBay do not see the item.
https://www.ebay.co.uk/help/selling/managing-returns-refunds/appeal-outcome-case-seller?id=4369
@maya-4401