Sellers don't need to open unpaid item cases any longer. Instead, orders can be cancelled if a buyer hasn't paid within 4 calendar days. If you still have open unpaid item cases, you have 36 days from the date they were opened to close them. If you don't close them within 36 days, eBay will close them for you, but you won't be eligible for a final value fee credit and the unpaid item won't be recorded on the buyer's account.
https://www.ebay.co.uk/help/selling/getting-paid/resolving-unpaid-items-buyers?id=4137&st=12&pos=1&q...
