Ebay issued a refund without my permission

I revently sold a Samsung tablet on Ebay for $330 this tablet had no cracks at all (There's photos as evidence on the Ebay listing) it was also wrapped up in multiple layers of bubble wrap. When the buyer has received this item they have obviously dropped it or done something else to crack the back of it. When I refused to issue a refund and accept a return they opened a case with Ebay and Ebay accepted a return and has authorised a refund despite me saying no. The first person I spoke to on the phone who was one of the rudest people I have ever dealt with told me that my only option was to reply to the email that Ebay sent me about the case, which I did and got no response. I am now going to be out of pocket for the Ebay and PAypal fees, and also have to pay return postage on an item that the buyer has damaged. I will definitely not be selling on Ebay again.
What are my options here for disputing this?
Who can I contact other that the ACCC in regards to this?