To be honest, so far the issues buy etc have only been with Ticketek (no surprices there) and not the Nix fault.
Trouble logging on, getting it to recongise renewal prices instead of new prives and credit card failing are all Ticketek.
What can the club do though? They have to use Ticketek as the provider of choice (contracted) to Westpac, sure they can jump up and down and complain but really its the only provider they can use for the memberships. So unless Ticketek ups their game and gets a better system and customer service (Brenda was a god send if you were willing to pick up the phone) then the Nix are stuck with who they have got as the provider of choice to the stadium