So how come that when I opened an etrade account last year it...

So how come that when I opened an etrade account last year it reactivated my old ANZ accounts that have been closed for years. I started to get letters telling me I was overdrawn. Of coarse this was the monthly fees that had restarted. It was good fun telling the ANZ to go to hell though as it was their mistake. But still if they are so seperate in legal terms then they should not be able to reopen old accounts!