claimed he was based in Sydney and was checking on some cyber security in relation to a credit card - could hardly speak English - when i asked for his number so I could call him back he hung up - when I dialed the number recorded on my phone I received a recorded message that said "the number you have dialed is not in service"

I just blew my whistle really loud

Caller: Robodialler

Robodialler. Just hang up. They want to know if there is anyone answering in order to call later with some criminal intent. DON'T SAY ANYTHING. Hang up.