Atleast in my country, to send legitimate marketing e-mails, a user has to be given a choice to opt-out *before* the first e-mail.
So it's not enough to allow them to opt-out with an e-mail exchange or an unsubscribe link, you must allow the user to opt out when you initially gather the contact information.
If that wasn't done, it's illegal (and unethical) to send marketing e-mails, even from a paid service.
So it's not enough to allow them to opt-out with an e-mail exchange or an unsubscribe link, you must allow the user to opt out when you initially gather the contact information.
If that wasn't done, it's illegal (and unethical) to send marketing e-mails, even from a paid service.