If they do not have unsubscribe links or headers that allow your email client to unsubscribe then email rules matching their keywords that either reject their emails with "Invalid User" or put the emails in a folder and mark them as read then check the folder once in a while to ensure friends did not end up in it. Options depend on the rule limitations of your mail provider.
If they are selling your address cross-marketing into dirty lists then report every email as spam to your email provider. If that does not help register on SpamCop [1], configure the hosts you send and receive email on and then paste the email headers into their interface. Their database is used by a number of providers as one of the factors to determine spam score.
[1] - https://www.spamcop.net/anonsignup.shtml