Most companies use a service to send their newsletters. You should be able to find the IP address from the email headers and then find the abuse email for that company. Email them, tell them you are unable to unsubscribe and their customer is thus sending you spam. Attach the email headers and 90% of the time they will take action (at least from my informal observation when I used to do this).
Most companies use a service to send their newsletters. You should be able to find the IP address from the email headers and then find the abuse email for that company. Email them, tell them you are unable to unsubscribe and their customer is thus sending you spam. Attach the email headers and 90% of the time they will take action (at least from my informal observation when I used to do this).