Getting rid of Apple Music which I have never used but am billed monthly!

You need to cancel it to prevent further billing:

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.

It will take effect on the next billing cycle. While you’re in those subscriptions- check to see if you have any Apps also billing you or about to, if you don’t cancel them.

and you can check your purchase history to see what’s been charging you in the last 90 days,