Hello and welcome to Apple Support Communities, d-esttt!
We understand you're not able to listen to Apple Music even though you have a subscription. We'd be happy to provide information to help you address this.
Check to make sure that you've allowed playing music while on mobile data in Settings > Cellular and make sure Music is enabled.
If this is not the issue, please let us know what shows up when you try to play music.
Have a great day!