Phishing?: "your AT&T Wireless phone number disconnected"

Received an e-mail from no-reply@myidentity.norton.com with the above advisory in large bold type and a big button to click to "Manage Phone Number," along with other embedded links. 

The rest of the e-mail looks letter perfect.  Here's the thing:  I have never had an AT&T phone or account.  I checked my Norton account inbox and it shows no messages.

I reported the e-mail to Norton, forwarding it as an attachment.  Anyone else encounter this?