Yes, I'm afraid if you do not close a transaction down correctly, you are charged eBay fees the second an item sells, so two sales, two sets of fees to pay.
For all non payments you need to inform eBay about these , by opening an unpaid item case in the Resolution Centre, link for this at the bottom of most pages. You close it on day 5, your seller fee is refunded, the buyer gets a non payment strike, and only then, are you safe to relist that item. The first transaction closed completely, and the FVF refunded for it.
