If you cancel at&t internet, will you loose your old ISP issued email address?

A friend of mine is trying to convince his parents to ditch their At&t DSL that they've had since it first became available. They have an old SBC global email address that they've had forever as well.

They're scared that if they cancel their AT&T internet service, they will lose the SBC Global email account. I would think that since it's all nested under currently, they would still have access to it just like how you can still have an att.net address even after you cancel AT&T internet.

So what should I tell them? They are paying out the a$$ for very slow and unreliable DSL internet when they could get cable internet for less than half the price they're paying with att. But it's all about that email account that they don't want to lose.