Refusing to pay due to joint banking account, refusing to check my arguments against their decision

I deposited $30aud at King Billy Casino with a Visa Card that belongs to my wife for a joint account we hold. I tried to verify my account prior to withdrawing my winning of $4000aud. The casino told me that my account could not be verified as the card was not in my name and even thought I explained that the card belonged to my wife and she had written and signed an authority letter to allow me to use her card and I could prove everything, they did not ask for any further documents and instead took away my $4000 that I was going to withdraw and wanted to refund my the $30. I said not to refund the money as I wanted to withdraw my winnings as I did not believe they were in the right as the account the VISA is linked to I have the right to use as my name is on the account. I have all the documents to back this up but I believe I was not given a fair chance as the casino didn't even ask to see any further documents and therefore did not allow me to withdraw. I would ultimately like my account verified and able to withdraw my winnings of $4000aud.
I have attached a copy of the transcript of my conversation with the casino and my account statement which has both mine and my wife's name.
I have all documents but am having trouble uploading them. can I please send them to an email with a complaints number or is there another way?
Thanks
Danny