If the buyer opens a not as described return request you have to accept the item back and refund in full.If you don't then ebay can refund on your behalf and place a defect on your account for not complying.
(No returns excludes items that are not as described/damaged)
If the item comes back in the same condition as sent,(no broken zip) then you can report the buyer for a false claim
Also look to add the buyer by User ID to your blocked bidder list here, https://www.ebay.co.uk/bmgt/BuyerBlock?
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