Prerecorded in American accent from security money transfer asking if I authorised transfer for purchases from Amazon $400aud and another $1200 from somewhere else as it sounded suspicious to them. Wanted the first four digits from my credit card to check. When I asked where is he ringing from he said from Commonwealth Bank. I told him that I cannot give him the first four digits as he should have those detail before ringing me on a private phone line and that I am not a commonwealth Bank member. He just hang up.