I think you take the risk if you send items overseas without some sort of tracking.  The buyer may be covering themselves before their opportunity to put in a not received claim ends just in case their purchase does not arrive before then.  However you will probably find that your chances of winning a dispute without some sort of evidence of postage are slim irrespective of whether the buyer took up that option or not. Best thing would be to ring Paypal and discuss the matter with them and ask about your postal receipt and how to send that through.  Good luck.