I’m not a BNZ staff, but have researched into this before.
In the payments sections of the T&Cs:
" How we apply payments: We will determine the way
payments to your Credit Card Account are applied. We generally
(but are not required to) apply payments in the following order:
a. to the ‘current balance’ shown on your statement, in
descending order of amounts attracting the highest
interest rate to those attracting the lowest interest rate. We
will apply payments to those amounts in the order of:
b. Where the ‘current balance’ has been repaid, we will apply
payments to any fees, interest and Transactions debited
since your last statement, in the same manner as above.
Regardless of the above, if you have made a payment that
results in your Credit Card Account having a credit balance, that
credit will be applied to any future Transactions in the order
that those fees, interest and Transactions are made or debited
from your Credit Card Account"
I think the reasons you’re facing the problems is to do with ‘hierachy of payments’.
Payments will always go to STATEMENTED items first, before NON-STATEMENTED items.
STATEMENTED items means what is already listed in your most recent bill (items that show up on your Online Banking does not count… only those in your last statement).
So say, if your 20 August bill is showing $352 due to pay, and now (9 Sep) you withdraw $100 from an overseas ATM, you must pay $452 to clear off the $100 cash advance.
This becomes more complicated if since 20 August, you made some purchases, say $50.
In this instance, paying $452 on 9 September will pay off the $352 from the last statement, $50 from the purchases… and you have $50 there, getting ready to pay off the $100 that will hit your account the next day.
But paying on 11 September (the next working day), when the Cash Advance had shown up, paying $452 will pay off $352 from the last statement, $100 from the cash advance, and you still have $50 from the purchases that is not yet paid.
Hope this helps!