Caller rang and advised they were from the Visa and Mastercard security team. They advised that there had been some suspicious transactions on my card the previous night and they wanted to confirm if I had made the transactions (no doubt so when I said no they could ask for my card number to put a 'stop' on them).

I asked where they were calling from they repeated Visa and Mastercard Security Team. I again asked where they were calling from, they said head office in Sydney. I hung up on them.