After a free trial you are automatically subscribed unless you cancel it. The first thing to do is to cancel the subscriptions so that there are not further charges. Please see:
Manage your Apple Music subscription - Apple Support
View, change, or cancel your subscriptions - Apple Support
As to refunds, strictly speaking all purchases are final (after all, you can't very well return them): please see this page for information on requesting a refund: Request a refund for an App Store or iTunes Store purchase - Apple Support
However Apple have been known to be sympathetic in cases of actual error (though I don't know whether failing to read the documentation would be acceptd); it's possible that they may allow you a refund as a one-off concession: but please be aware that they are under no obligation to do so: go to iTunes Store - Contact Us - Apple Support
Alternatively go to the page suggested in the Help page linked to above: Report a Problem