For sellers registered under eBay Powership programme, eBay automatically confirms item delivery based on courier status. So if you've received the item, and the status shows 'Delivered' on courier website, ebay will update its synchronized records. If you dont receive the item, either of the following happens-
>Receipt isnt confirmed,
>Item has been incorrectly scanned during tracking resulting in false AWB
>Or probably someone els has received it on your behalf!
Unfortunately one primary backlog is you cannot directly file an 'Item Not As Described' claim if it has been Powershipped. Although you can alwaz file one under 'Ebay Guarantee' or Resolution Centre, and coordinate with Customer Support(CS) regularly for a speedy resolution