Apple music

If you just created this Apple ID and have never redeemed the Apple Music trial, then you will need to contact iTunes Support as they may need to do something internal to the account to enable the music trial.

See here: https://www.apple.com/emea/support/itunes/contact.html

Apple Music is available on other devices including Windows computers and Android phones and tablets, so its entirely possible you used the one free trial on one of those devices. The trial / subscription gets tied to your Apple ID, not a specific device.