Similar to above descriptions.
I intend to annoy THEM by phoning the number and asking questions if any answer. It is useless reporting to Telstra, as they do nothing! I intend contacting police this time if I get an answer!

Said they were crime investigation blah blah blah before I hung up

Caller: not sure, claiming to be from telstra...

claiming i have inter net issues, slow speed n more. I terminated call after approx five minutes. Seemed a bit dodgy. Be wary.

said something then hung up

Recorded message by male with American accent claiming to be important message about tax.

Received Automated phone call regarding "Suspicious government activity". It then went on to ask me to visit a "suspicious website". Clearly a Scam.

A call received purportedly from EBay informing me that I had purchased $300 iTunes cards from EBay. I do not use eBay but they had my email address and phone number. When I asked to cancel the transaction they asked that I install the AnyDesk app on my phone. This sounded very dodgy so I pretended that my phone was nearly flat and asked for a number to return the call. They hung up without providing a phone number.
Sounds like a scam but a bit frustrated that they had my email (albeit slightly incorrect).

Recorded message claiming from Amazon. Total scam trying to get me to "press 1".

had two missed calls from this number today, both times the phone only rang once before hanging up

Caller: Recorded message

Threatening message about suspending bank account and court order - press 1.

Not bloody likely!