Go to a place like Mailermailer and get a script there to place on your site to sign up people for a newsletter.
You can try it for free, signups are collected by mailermailer who sends out an opt in mail to confirm the person signed up for real and it’s not someone playing tricks on another person.
So you have a double opt-in, which run trouble free. If there are complaints, mailer mailer deals with it. The stats rock, you can get to know your players because you see who clicked on what and you can follow everything.