This is strange as my listings are charging up to double the postage cost. Something is definitely wrong 

I am having the same issue with the postage, as well as a lot of listings saying "Will post to Australia. Read item description or contact seller for postage options". I am an Australian store and have not amended any of our postage policies. No wonder people have been messaging saying postage is too expensive, I never realised what was going on! For example, a small item weighing 200g with measurements of 15x15x10 is charging $17.43, instead of $9.70 I think it should be. I've also noticed it undercharging postage on orders by only a $1 or so, and thought that was odd, but now it all makes sense. Something is glitching on their backend. I am going to contact them today and lodge a complaint. This is affecting sales at the busiest time of year.

I just received an international sale (to Norway) 

Lucky that I added $3 int. handling fee on all my postage policies other day.  it covered the underpaid postage (at least for up to 250gr items) . It looks like eBay IT guys messed up again.  Have a look at this Ebay int. postage calculator. Looks like the IT guys did not understand this easy task to fix the issue. Did you see the mistake they are doing? They are using the existing Australia post services to define their new discount postage, so there has to be another 2 new lines as a new postage service options "ebay postage label int. standard" and "ebay postage label int. express" 

This is the postage policy page / int. Postage options

There is no ebay postage label option showing. 

And some of mine are showing as 'Pick Up Only', now ! Just pathetic.