Rang and hung up. Thabks to other comment about NAB scam. Blocked.

I received a call from this number purporting to be from NAB and checking whether I had authorised a payment for medical expenses in the US.

It sounded like a noisy call centre and probably in India.

The operator wanted me to download an app called anydesk and was then presumably going to step me through a process to allow them to ‘check’ security on my iPhone (or alternatively might have given them remote access to my phone).

Anyway, I asked to call back via a NAB phone number, but they persisted.

So I hung up and called NAB to check. All ok with my accounts and the NAB operator asked me to take a screenshot of the number and send it to phish @ nab.com.au. He also advised changing passwords and blocking the number.