Apple music

First Verify your membership is active:

View, change, or cancel your subscriptions - Apple Support

you can do this on your phone in settings or as instructed in the above link 

Go to Settings > [your name] > iTunes & App Store.

Tap your Apple ID at the top of the screen, then tap View Apple ID. You might need to sign in with your Apple ID.

Scroll to Subscriptions, then tap it.

Tap the subscription that you want to manage. ...

Use the options to manage your subscription.

if it’s just not letting you play music:

If you can't download, play, or access songs

First, check iTunes to see if the song is ineligible for upload. Additionally, if you added the song to your library from the Apple Music catalog, it might no longer be available on Apple Music.

• Reset Network Settings
• Close then Launch  Apple Music App
• Restart Your Device
• Sign out of Apple ID and sign back in 
• Turn off and back on "Show Apple Music

• Update Apple MusicApp.
• Update iPhone Software.

Turn on iCloud Music Library with Apple Music

https://support.apple.com/en-ca/HT204926

Turn iCloud Music Library off, then on again

On your iPhone, iPad, or iPod touch:

1. 1. Go to Settings > Music, then tap iCloud Music Library to turn it off.
   2. Close Settings.
   3. Go to Settings > Music, then tap iCloud Music Library to turn it o