AVDATA is a privately owned business that appears to have little scruples in regards to making money. Their methodology is to bill first and hope no one complains. We had an AVDATA data recorder at the airfield about 13 years ago, despite telling them not to bill certain aircraft they did anyway, we then discontinued the service but they still sent bills out! (money was sent to someone else, not us, and took a bit of digging to unravel the situation). Took legal action before we finally got rid of them.
It was very disheartening to hear that RA-Aus would no longer pass on accounts for landing fees but recommended registering with AVDATA! Running a private airfield is VERY expensive, council owned ones should be a bit cheaper (no rates etc, more equipment etc) so I do not begrudge landing fees at all, but if I can I prefer to deal directly with the airfield rather than through AVDATA.