I called number (02) 8397 1204 and spoke with a female agent name Rachael.
She said she is from commonwealth bank and based on the IVR its commonwealth bank.
She was asking my date of birth so that she can determine why someome from their company called us.
She wants to verify who I am first before she can give instructions on how we can opt out from their calling list.
I wasn't able to get were they are calling from.

I had a girl call my mobile on my work mobile saying she was from the commonwealth bank. She wanted to verify my details and said that she couldn't tell me why she was calling unless I verified the details with her. She then directed me to go to the local Commonwealth bank and they can advise why she called me. I called the commonwealth bank and they said it was a SCAM, and they were working on it.