I've just found out that my phone number has been spoofed. I see that a few other people have mentioned this problem to the Community but have seen no reference to suggestions Boost might have about this.
I contacted Boost via the Chat function and was told "everything is fine and nothing to worry about". When I said that, of course it was worrying that someone was pretending to have my phone number, they said they could transfer me to the Faults Team. The person I was connected to at the Faults Team didn't seem to understand the problem and after being on the chat function for an hour, I had to leave the conversation due to other commitments.
I'm posting this to alert people to the fact that the problem continues to exist. The Australian Communications and Media Authority suggests that this problem be reported to the telco, but Boost seems to have little interest or understanding of the problem.