someone using one of my iCloud email addresses
I received an email to one of my iCloud email addresses from an internet provider that I do not have an account with. The email was addressed to someone I don't know, full name, address, account number, security code. It was an email for new internet service. This has happened before twice, with same iCloud email, but different companies. I called the internet provider and all they did was make notes and confirmed that the email was in fact sent from them.
My question is how does this happen? Does it mean my account has been hacked? What to do? I have a support request in to Apple.
MacBook Air