What is 'Unpaid Item' Report Timeframe?

It is a period of time when a seller is allowed to open a dispute about an Unpaid Item he sold. Usually, there is a certain period of time between minimum and maximum number of days he can do anything about his an Unpaid Item, such as claiming a 'Final Value Fee' (FVF) back as well as making sure a buyer gets NPBS strike. Currently, a seller can only open a dispute at least 14 days after an item ended (regular auction or buy now), and not later than 45 days after the item ended.