After four days have passed, you are able to open an unpaid item case, which then gives the buyer another 4 full days to pay before it can be closed for a refund on the final value fee charged.
As it's a pick-up item, and was sold at a fairly busy time of year, I would suggest perhaps giving them a phone call (you can request their contact details if you need to by conducting an advanced search via the link at the top right-hand side of the page).
I would advise against relisting until the original transaction has been finalised, as it has the potential to mean you have two buyers for the one item (i.e. sells on relist, but the original buyer can still pay via PayPal unless the transaction is cancelled by mutual agreement or UPI case).
