Before jumping to the conclusion, I think I'd better mention some additional information I did not mention earlier.
Commonwealth Bank (CommBank) upgraded my credit card since I first signed in with PlayStation Network, which means it is a different card number instead of just new expiry date.
According to my conversation with the Bank, Australia does not allow address verification on credit cards, US companies does. However, my billing address is as printed on my credit card statement.
Further, CommBank recently released American Express card on top of MasterCard and Visa credit cards. I might have been locked out by PlayStation Network due to trying to use American Express card, before I tried to use MasterCard.
PlayStation Technical support told me that I would be locked out for 24 hours due to a few wrong attempts, something like 5 times.
I've been entering my credit card information elsewhere with proper case (mixed upper and lower cases, as in normal spelling style), and it all worked fine.
I personally do not think that upper/lower case is an issue. The only reason I pointed out was because all other recommendations (on other gaming forums) all suggest using ALL CAP in entering if the address in statement is printed in ALL CAP. Obviously, those who get through successfully did not bother posting online for help.
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