That’s quite a saga. As to your questions:
Why won’t NCAT accept my bank statements as proof of payment?
I have no idea. You would have to ask them. But it sounds like they have refuse to make a ruling (because there has been no hearing) not that they refused to acknowledge the payment. Two differnt things. I would be asking that the owner shows the bank staements from that account for the dates that your statement shows the payments were made (and from an account that shows other payments from you).
Can NCAT actually order me to enter into a formal investigation with the banking ombudsman?
I wouldn’t think so. They are more likely to ask the owner to do as I suggested above.
Is there anywhere I can get proper legal advice from someone that actually knows this area of the law?
Try Redfern Legal Centre, who specialise in residential tenancies. Or either of our sponsors, Sachs Gerace Lawyers or StrataAnswers.