The skimming techniques they have can keep random dialling until they reach a connection.Do they not sell BT Call Blocker phones down under (or equivalent)???
Call blockers especially for landline is fairly ineffective , you have to block them on a number by number basis but VOIP is random from a random generated number in essence.
the old story you play your favourite tune to make it worth your while.
For me its Tubular Bells today , what a genius Mike Oldfield was at 18 better than any scammer will ever be.
Almost 50 years to the day he started composing the music.