Receiving emails in my iCloud account that are addressed to another user name that is not mine

Over the last year, I have been receiving emails from a username that is my wife's name but has no association with my iCloud email account. I went into my iCloud account to see if we had accidentally set up an account and associated it with our iCloud account but there is no such account. Also, when I try to log in to iCloud using this supposed email it says it does not exist. Furthermore, the iCloud email in question arrives in my existing/regularly used inbox. Somehow, it appears as spam. Somehow, it ends up in my inbox but under a different username. I am baffled. The emails that come are confirming subscriptions to Monat or to Dolly Parton Stampede. It looks like possible "phishing" or something. Any ideas on how to stop receiving these emails?