I called back number (02) 4485 6934 rang 2 times then goes to busy tone.

it is a scam

Yep just got a call and they couldn't verify any of my details but kept asking me to verify mine.
I told them if they were from the NAB bank they would have all my details but they couldn't give me any. bloody scammers.
Called back no such number.

Ring me 3 times a week in the afternoon for the last 4 weeks, sometimes twice a day, picked up a couple of times and asked them to repeat what they were calling from and about they hung up on me. Couldn't block the number.

Claimed they were from NAB bank. Looks like a quite sophisticated scam to empty your bank account.

Rang 3 business lines all at once and hung up. Called back and line was disconnected.

Couldn't understand a word they were saying told them to send me an email and they kept banging on about electricity 30% or something so I hung up