I have the same problem and I'm not sure what to do about it. I don't open them. I opened one in the past thinking there would be an unsubscribe link somewhere and when I clicked on "unsubcribe" it would just bring my into other sites.
I don't know if this will help you because I don't know how to STOP the email from getting to my mailbox but when I do receive one, I add it to my block sender list and then delete it (without opening) so hopefully I won't receive anymore from that particular sender. It has cut down on the number of unwanted email that makes it to my inbox.