Caller: Smooth operator wanting me to join his club

Telstra person (fake I think) asking permission to be my comms account Manager and in return receive Telstra discounts and special offers through his bulk buying agency. Don't fall for it.

Caller: Advanced Scammer

Advanced Telstra account takeover scam. On answering, you will be transferred to Telstra's legitimate IVR, however a scammer will be listening in to your conversation. If you proceed to try and get connected to someone through the Telstra IVR, once you finish passing the identification check (and 2 factor authentication SMS), the scammer listening will cut you from the call and talk in your place, trying to ultimately add themselves to your account so they are able to control it.

Due to Telstra adding 2FA to most accounts, this is one of the few effective ways to gain control of an account. The primary reasons for wanting to do a takeover would be to either add services to your account, or to perform a sim swap so they have control of your phone number to generate 2FA tokens for any services you might use SMS 2FA for, like banking.