The opt-out of the newsletter only works if you are logged in. If you don't know your password or are mistakenly on the email-list, that's bad. Please change it so you can opt out of the newsletter simply by clicking the link. In some countries this a legal requirement for sending newsletters.
I have also attempted to opt out via the contact form and by replying to the email, to no avail. It would be nice if you read your email 🙂
Thank you!