Package sent through Global Shipping Program not delivered. Now what?

[bfmike]

I shipped an item that I sold to a buyer in the Netherlands.  I purchased a shipping label through Ebay and sent to their Global Shipping address in Glendale Heights, IL.

I see the package is marked as shipped, but not delivered. 

Buyer is threatening negative feedback, but I shipped the item. Now what?

[bfmike]

I should also add that USPS tracking shows that the item was delivered to the Glendale Heights address.

[bfmike]

Is there anyone that can respond to my original question?  I'm at a loss as to what I'm supposed to do.