Problem is, if you filed the case with Ebay and you have the tracking number for it it's best to let it run its course, else you'll still have to pay the fee to Ebay for the original sale. If you let Ebay fix it (it might take a while) you'll get your fee back or they will get the buyer to pay. I had the same thing happen a month or so ago. Took Ebay about a month but I got the money and shipped the item.
If the case is opened, when you first sign on to Ebay, click (in the upper right hand corner) My Ebay followed by clicking on "Summary". When that opens part of the sub-headings will note if you have any cases opened...
Hint: don't leave any feedback until the item is received and see what feedback the buyer left...