Retailer Non compliant with CPA

It's amazing how a huge retailer goes against CPA. Purchased a waterfall fountain pump 20 days ago and it stopped working after 15 days. When I took it to the Newcastle store today, I was told that it will need to be sent for testing. I was told the store had the right do decide on what to do. They refused to refund me yet the the product is defective and purchased less than 3 weeks ago.

The store is 65km away and I made a special trip to get it replaced or refunded.