If you added extra credit to your account (beyond the price of your plan), then you can make calls to Australia for $1.09/min.
However, if you also purchased the International Call Pack, you get calls to Australian landlines included.
But if you call an Australian mobile, it is still charged at $1.09/min (there are no International Call Packs that cover calls to Australian landlines).
So, if you did purchase the International Call Pack and got an SMS saying you were charged $X to call Australia, then it is because you called a mobile. Don't worry, many customers get all confused and swear it was a landline they called, but when they actually check, it was a mobile.
If you are 100% certain that you purchased the International Call Pack AND your call was definitely to an Australian landline, then please email us at help@usaprepaidsimcard.com.au or create a New Ticket above.