Don't email them to ask to be taken off their email list, this too verifies your email address. Most email programs have filters, to help you filter out mail you don't want, if that does not work, the delete button always does. Never give up your passwords . Contact the company by looking up the phone number or email address on your own, then contact the company with the information. You can't eat these Cookies.
Web cookies are a little like fingerprints for the internet.
When you receive them they are checking to see if you have the right stuff and when you give them, you are giving a reply cookie. From these a webmaster can see who you are, what browser you are using, etc.,etc,etc. The more you surf, the more Spam you will receive. Try a cookie blocker software. There are a couple good ones out there.