According to this Time Zone Map...

https://www.timeanddate.com/time/map/

...you do have your time zone set correctly. The calendar listings for the chats (that look like this)...

This event occurs every 1 week(s) on Sunday
12-19-14 to 10-07-18
01:00 PM to 02:00 PM

...should show Melbourne time. If your chat reminders are still coming at the wrong times, would you mind posting again with a specific example? For instance, "The clock on my computer says it is now (Time A) in my time zone. I just got a chat reminder that says (name of chat) is happening at (Time B) but according to the calendar, that chat is actually scheduled for (Time C)."