After 4 days as Ed said you can close the case and then relist. The buyer has 4 days exactly from the time the case is opened. close the case and relist. Buyer can not leave feedback and receives a strike against their account.
If you have your
ebay unpaid item assistant set to automatic it should be a done deal after 4 days, if you have it set to manual, then you have to go to the case in the resolution center and manually close it.
let us know how you make out.