Tracking says delivered but it hasn't arrived, been a week
This is a fairly common situation to happen. Tracking shows delivered but the buyer claims they didn't receive the item.
Whether your the buyer or seller in this situation this video describes how you should handle this situation and how it will play out.
Typically the seller will not be out money if they did everything right on their part and the buyer will typically be credited by eBay and not the seller, assuming they don't have a history of claiming they didn't receive items which show delivered.