Emails in Icloud mail

I have been receiving emails in my icloud mailbox that are addressed to other email addresses but yet address me when I open them. They’re all adds to buy products (spam for me). How did that happen? So if I go to unsubscribe, I unsubscribe a different address than mine...and I still receive the same emails with another different address! My icloud mailbox used to be so “clean”, now I get several of theses everyday! How do I fix this!