Qff - I had the same problem last year. Spoke to Avdata who put me forward to the rottnest island authority who directed me back to Avdata - love a good run around.
In the end I told Avdata to contact the island authority who's argument was that by conducting an approach you prevent another aircraft from landing. Pretty lame. They don't provide any service therefore they have no right to charge for a missed approach.
Long and the short of it the charges were waved. However they check the tapes and needed reminding each time a bill came with a landing chArge on it