Someone else shares my name@me.com. How did this happen?

I get emails to the now-defunct name@me.com email address (that was transformed to name@mac.com in the not-so-distant past) that update me on the user's purchases of Starbucks Gift Cards. I thought that the name@me.com email was mine alone to keep in perpetuity. I have tried to delete it to no avail. But still these Starbucks' purchases are sent to me and occasionally junk mail comes to this address.

I only use the name@mac.com email. How can I delete the old useless name@me.com email address.

P.S. Fortunately, none of my credit cards were associated with the old address so I'm not getting billed for Starbucks' cards. It's simply annoying. Thanks for any advice Mac community members.