This sounds like the item sold but the buyer is yet to pay. When they pay eBay send you a message to say Buyer Has Paid, and then they provide the details for the name and address to ship the item to.
The item will stay for sale until payment is made by the buyer and indeed is open for another buyer to come along buy and pay. A buyer does have 4 days to pay.
Personally, I have found when I've accepted an offer sometimes the buyer hasn't paid thinking that the acceptance means they have. eBay send a reminder to pay after 48 hours, if this doesn't work I send a polite reminder to pay and send an invoice.
Some will say this sets the clock back giving the buyer another 4 days to pay, but for me the buyer then has paid straight away.
@wenceslas09
