Bank rings you and yet asks you to identify yourself

I always find this bloody rude quite frankly. Today I had NAB (great and appropriate name for a bank btw), as I had just set up a new account with another bank and transferred monies from my NAB account to this new account. NAB ring me afterwards. Can I identify myself - well no - you rang me - who are you.. I say to this guy I transferred x amount to y bank. I see no need to identify myself. Guy says you dont have to identify myslef, I think great - who needs to go through that stuff... A few minutes later I get a text saying my internet access has been blocked!!~!~! WTF. I was not warned this would be a consequence. The amount transferred was not in excess of my transfer limit nor was it in excess of the crime reporting limit. It is my bloody money. The bank rang me! I was so furious, then ofcourse trying to ring them back, having to enter numbers that you have to go and search for.. Then I had to explain what I was doing with my own money and why! I think NAB just lost a customer. No, I don't think this is appropriate anti-scam process. Whoever designed the process has watched too many noir movies on Netflix. I was even asked if I had voluntarily set up the new account with the other bank!!!!!