[OT from Cash Advance topic bit removed …]
… and re Settlement Date:
If your payment is made on a bank business day before 6pm (Sydney / Melbourne time) it will be debited from your account instantly and processed that day. The biller will acknowledge the payment as having been made that day and should process the payment the next banking business day.
If you make a payment on a weekend or public holiday, or after 6pm (Sydney / Melbourne time) Monday to Friday, the payment will be debited from your account instantly and processed the next business day. The biller will acknowledge the payment as having been made on the next banking business day (this does not include weekends or public holidays).
Lots of other examples of settlement date - getting too far OT …
I reckon you could fight it !!! 
Seriously though, closing date, due date, if you ‘settled’ on the ‘closing date’ they’d still likely be in breach of their agreement if they rejected it - they still have a biller agreement - might need a lawyer though, like the Commonwealth Ombudsman told me I’d need against a government department who did similarly. Essentially they seem to be accepting a method of payment that is apparently incongruent with their internal financial processes … it would of course be simple to just advance the due date, closing date or whatever they’d like to call it by two days to mask their internal imperatives … but why do that when you can make it the customers problem to be on time …
