Buyer wanting refund for item broken by Aus Post

[reallygoodbits]

I recently sold a small Chinese ceramic container & packed it in bubble wrap with styrene beads plus cardboard & then put it in a bubble pack. Buyer did not pay insurance but I understand that Aus Post will refund broken items under $50 if they are well packed. I told the buyer & he took the item ( I have seen the pictures of it broken so he is telling the truth) into his post office & they said it was insufficiently packed which is why it broke. Not sure what else I could have done. Haven't got styrene packaging. By the pic it looked like it had a hard impact as it was in quite a few pieces. 

Does anyone know who I can ask the buyer to go to for a refund. It's not fair that I have to lose out. He wants $15 back & I only made about $4 form the sale in the 1st place. I am think there's a number to call at Aus Post?? Woudl love some urgent feedback... I'm a 100% feedback seller & have sent items all over the place. Tried emailing Paypal about the procedures when buyers want refund by they keep giving me answers that have nothign to do with the question.

Thanks in advance....