There’s a Do Not Call register, hosted by the Australian Government, at donotcall.gov.au. You can, in theory, register your home or mobile number with the register; “responsible” telemarketers then compare their shonkily-obtained “lists” with the Do Not Call register, and, theoretically, do not call you.
The Do Not Call registration page is here. Like many such pages, it includes a captcha to check that submissions are being made by a human. Almost all captchas check that the person is, in fact, not just a human, but a human who can see and/or hear, and that they are a human who is using sufficiently recent and mainstream web technology that they can see an image or hear an audio file.
There are still plenty of captchas around that use only an image file, with no other alternative for people who can hear but not see. Those are bad enough. The Do Not Call register is worse. It uses an image file with audio alternative: however, the audio alternative only reads the first 1-3 letters of the image, meaning that blind and visually impaired people who use screen readers will just get a failure notice over and over and over again.
How long has it been doing that? I have no idea. But on a day when there’s high publicity for the register in the mainstream news (numbers added when it first opened will expire soon), there’s no excuse for someone not checking the tech.