Is it possible that one of those charges is actually a credit?

If not, you should be able to contact eBay by going through the Help page:

https://www.ebay.com.au/help/home

Use the "Contact us" link and follow the prompts for your issue and you should eventually wind up on a page with a chat option. Choose that, and the last option that appears in the chat window -- use the "See more" option -- should be "Contact an Agent" to request a call-back if you are in Australia.

Or you can contact eBay via social media:

https://twitter.com/askebay

https://www.facebook.com/eBay/