It is up to you how long you want to wait for them to pay

As far as ebay 'rules' go, once it has hit 4 days (to the hour/minute) you can open an unpaid item dispute. Ebay gives the 'buyer' another 4 days after that and after that 4 days has passed you can then close the case to get your listing fees back

Just be aware there are many many scammers based in that country, it is possible you might get a story about them wanting you to provide bank details etc rather than go through paypal

Far better to be safe than sorry IF they do pay and only accept paypal and only post the item to the address given in paypal

If they don't pay, after you close the case, remember to add them to your blocked buyers list

Good luck, I hope you have a buyer who is simply slow off the mark rather than a time waster

(also there is the option to in future add / tick the immediate payment required on buy it now listings