Unfortunately yes, however if she contacts the buyer and points out the fact that it was posted immediately after payment, but that with the four day Easter weekend it has likely just been delayed (give her the tracking number so she can see for herself that Auspost have the item),a reasonable buyer will understand. She can ask the buyer to give it a few more days and when it is received, the buyer can go back to the dispute and close/withdraw it.  You may still need to argue with eBay to have the associated defect removed though.