Re: "Now I'm being charged monthly by Verizon and Apple."
Are you being charged twice?
If you are only charged by Verizon you will need to cancel through Verizon.
See the following from: https://www.verizon.com/support/apple-music-faqs/
How do I cancel my Apple Music subscription?
You can choose to opt-out of Apple Music from your computer or mobile device in My Verizon.
If you are being charged by Verizon and can't cancel as described above, contact Verizon support.
If you are being charged by Apple, see: See or cancel your subscriptions - Apple Support