Send them physical letters via snail mail, written on coconuts, or dead fish (dried ones still smell, especially on warm to hot days - and it is summer ).
They are bound by law* to keep all correspondence for x amount of time (where x is a value I cannot remember, but might be as long as seven (7) years), and coconuts are not the easiest of "letters" to store - and take up a lot of space.
I remember such tactics being talked about, and to some point used, back a few decades ago regards the Sunshine Coast motorway - to get the tolls removed.
.
(*At least they used to be.)