Paused and they said Hello. I asked what they wanted, and silence ... so I hung up and blocked the number

I answered. There was a pause. They said they were from Telstra Tech Support, and could they confirm my name and details. I told them I would not be sharing my information given they called me, so presumably they know who they called. I asked which Telstra they were calling from. They advised the purpose of the call was that they had noted changes to my internet and were curious if I had made those changes. I said thank you for advising and went silent. They hung up.
I immediately contacted Telstra on their call number and spoke with a lovely person who advised this was not something Telstra was doing, and it was most definitely a scam.
Stay safe. Please do not provide your personal details to people - that is the only currency you have.