Apple id

Apple will always address you by your name or the name they have on file for you, not Dear Customer, Dear Client or by using your e-mail address.  The e-mail will be from @apple.com or @iTunes.com. E-mail addresses can be spoofed. You can go to Mail/View/Message/Show all Headers to see more. Apple e-mails will never contain an attachment. Apple will never request personal information by email such as Social Security numbers, your Mother’s maiden name or full credit card numbers .

The only exception to the above I have noticed is if you order something from the Apple Store (apple.com), your receipt will be addressed to Dear Apple Customer. That is a receipt for a purchase you initiated.

That email was a scam. Apple doesn't sent emails if your account is locked. They notify you when you attempt to log in.

If you used a link in that email to respond and entered your Apple password, your password is compromised and you should change it immediately if you still can. See: If you think your Apple ID has been compromised - Apple Support

If you entered credit card information, notify your bank.

Also see: Avoid phishing emails, fake 'virus' alerts, phony support calls, and other scams - Apple Support

You are welcome.