Email details plus what else?

I used a mail address at a non-plusnet hosted domain that I own to sign up to plusnet's services, this address was a one-off for that purpose only and has never been used for anything else at all.

It is now receiving spam.

As this address was provided at the same time as my payment details I'm left wondering what other data are now in the hands of the viagra merchants.

Still, after losing a load of our mail it is thoughtful of them to provide us with some extra to make up for it.