"remove from list" nightmare?

while searching for info on free grants/applications, my addy was evidently 'shared' with a huge number of 'affiliated helper sites' who have been bombarding my mail with "free" this and that info/contacts. I followed the unsubscribe link from the original site of my inquiry but keep getting mailings that I must unsubscribe from....all of which seem to have the IDENTICAL unsubscribe page. How do i remedy this p.i.t.a. (pain in the a*!) ? Can it be done in one push of a key??? Please help me!!