It's a glitch on a Friday happens more often too, as it's eBay's maintenance day.
I've had this happen to me several times, and yes, it is unnerving.
However, click on the item listed for ' sale'. You will see top left it will state, this item has sold. There is also no way for anyone to buy the item again, Buy it Now / Bid here, is not present.
The item will just disappear or just end it. More Actions >> End item, or tick box left of item if on Seller Hub scroll up tp Actions >. End item.
