Only a seller can open/close unpaid item (UPI) cases. The buyer can only either pay or NOT.
Once a UPI case is closed it is finished on that transaction and cannot be re-opened.
If the buyer has not paid after 4-days you can open the UPI case.
If they still do not pay then after a further 4-days you can close the case to get your FVF fees back.
If you paid listing fees these are not credited, only the FVF.
Only after the case is closed you can relist the item (assuming you only have one of the item). If you have multiples then you can relist any time you please.
If you relist it before the case closes and then the buyer pays you might have a stock problem on your hands (if you had only 1) and for that you will get a defect.
If the buyer should choose to leave you bad feedback before the case closes you should be able to get ebay to remove the bad feedback after the UPI case is closed.
