There seems to be a lot of it about at the moment - the credit crunch must be bighting the fraudsters!
I have had two dodgy emails over the last couple of days about my Alliance and Leicester account and my Abbey account, neither of which I have.
If your Mum did type in the correct passwords to the email, it will tell her that they are incorrect and the fraudster will keep the real ones. On the other hand, if they were rubbish then the fraudsters can't do anything. If she cant get through on the phone, she needs to at least send off an email and keep a copy - paypal should cover her from the point at which she advised them that her account could be used fraudulently.