Good advice Adrian.
An ISP or a service like Hotmail will NEVER call you and ask for personal information. These phishers are looking to get into your web mail accounts so they can turn them into mass spamming tools. Somtimes they are used to spam further phishing emails, similar to the call she got, or to send illicit advertisement or spam in general. Worst case is that it is used to mass mail as part of a over simplistic denial of service attack on someone/something.
Depending on your ISP's rules and it's ability to watch it's traffic, your entire Internet account could get locked down when they identify you as a mass spammer. They have to do this to protect their entire network from being being blocked as a big spamming network. Usually a call in to their help desks can help you get your web-mail back in your control and you might also have to prove your PC(s) have not been infected with a spamming virus as well.
And your right, this sort of thing is way too common right now. It's a world wide issue.
