itunes will not accept my Credit Card entered is not valid in Australia what duh?

This is my first time I've got an issue with Itunes, I have to say I am APPLE biggest buyer and a loyal customer of APPLE but this error seems ridiculous. I've been using the same credit card in itunes with no problems till today. My last purchased was on the 3 March 2012, got 3 apps from itunes for my Iphone. Just this morning tried to get another app with the same credit card, comes with an error stating that

'The credit card you entered is not valid in Australia. Please provide a valid credit card for Australia'

I find this is totally incorrect, I had contact my financial instituation confirming that there is nothing wrong with my card which is true. I done searches in Apple Support regarding the error, implying that it could be the post code or the address, I can assured there is nothing wrong with my billing or postal address as it has always been the same. I don't see what would be the reason my card got rejected? This is very frustrating NOT HAPPY JAN!!............

Not a happy customer at the moment