AU PSN Store: 'Your purchase may not be complete. Check your transaction history in your Account settings.'

I've been getting this error for MONTHS. No matter if I try to pay via PayPal or credit card. The only way I can even make purchases is to buy credit from JB HiFi online, add it to my wallet and then make the purchase, which is just way too much dicking around.

Any other Aussie users having this problem? Is there a fix?