Recently Valve has introduced an "Australian tax", because they don't want to accept our Refund Law Policy, which allows consumers to refund whenever they please if unhappy with the product.

For example. An 80 dollar steam game is now worth over 110 when taking into USD Conversion and the new 10 Percent Tax.

Alternatives:
http://www.ozgameshop.com/
https://www.humblebundle.com/civilization-bundle
https://www.gog.com/

You can email Valve, but don't expect them to change. This is mostly the Australian Government's fault for being weak and not dealing with big Corporations not paying Tax.

Physical Retailers such as EBgames and JB are now cheaper... Think about that for a moment. Pixels cost more than a physical copy.