‘Not in service’ message is fake. Call is answered and you pay for it.

Voice message is not a genuine Telstra or other network voice talent.

Some sort of debt collection call centre hidding company name.

Number called but phone said suspected spam. No message left so checked here & saw earlier post - will block now

Caller: (03) 8657 0524

Glad I checked this .
Always Google an unknown number from your phone first and it will lead you here. Just google the actual phone number with the area code.
I suspected scam and sure enough it was!
Don’t ever respond to a call at first sight .
First instincts are right instincts! Hope this helps others .