Second call from this number but no message left. Blocked

Rang and left no message. Most of the NSW/Canberra calls I get generally are scams so I am guessing this one is too.

No message

No message left - caller was from Terry HIlls NSW - I have received a series of calls from telemarketers in the past week and have blocked each - seems coincidental that again today another call from an unknown number has occurred with no message left

2 calls and no message left.

called no message another scammer

left no message. Blocked number

Called twice. No message left.
I didn't call back.

I've had a series of 5 calls calls with (02) prefix within 30 min ..several different numbers...nine leave messages and when I've called back, it cuts off...I've blocked.

Rang, I answered, nothing on the other side. Left no message.

Why do they do this?
Fulfilling a call quota? Testing waters?