Hi,
I am just testing it now, and I am getting the same problems. 3 small items in the cart and the express post shipping is $30, when it should be $13
That's because you have set the "Group packages" option to NO through your Australia post shipping method, so you'll have to send one package per item instead of grouping your items which will be more expensive.
Also, I am getting the same problem when testing the delete button. Deleting 1 product wrks fine, deleting a second product works fine, deleting a third or fourth product creates an order.
Can you download the last Hikashop version through our website, install it and test it again ?