I previously had issues with Optus for months in t...

I previously had issues with Optus for months in trying to cancel an account with them. Optus continually apologised and confirmed multiple times I had nothing owing and gave me a credit.
Next moment, this company is calling and harassing me.
After being called, they asked me to confirm my details and I asked them to confirm theirs first: check mate.
This was from a normal looking number. I blocked it afterwards.
Ongoing calls and harassment from a private number after that.
Never let anyone call YOU then ask YOU to confirm your details! They should already know who you are if they are calling you!
Scam scam scam!!