Hangs up when answered

Seems to be a chain of mobile numbers who call and instantly hang up using this number and many others 0408 008 xxx

The numbers call twice daily and whoever is calling calls on a different number with different three digits.

Other numbers I had had calls from so far are:
0408 008 744
0408 008 742
0408 008 765
0408 008 760
0408 008 776
0408 008 784
0408 008 756
Etc etc etc.

Hung up as soon as I said hello

Same as the comment from June 10 2021 - Seems to be a chain of mobile numbers who call and hang up quickly using this number and others with the pattern 0408 008 xxx. No message left.

The numbers call daily with the same seven starting numbers and different last three digits.

Other numbers I have had calls from so far include:
0480 008 744

Spam

Didn’t answer but looks like it’s a nuisance call