Receiving two Ten Tabs to a single email address

Hi there, this is strange indeed. For us to investigate further though we will need your email that is subscribed to your account. I will send a private message to you (you will see a red dot next to your avatar on top right of this page), so you don't have to write your emails in public. Also just making sure, you haven't subscribed with a relay account, right?

The other (gibberish sender) registration would be with Apple's private relay function. If you look in your iOS/macOS settings for iCloud features or mail, it will list fake mail addresses created for you, when, and why (which site) — that will help you figure out whether that's the relay subscription you want to remove.