Unfortunately, per our Terms of Use, we're not able to refund memberships. However, you're able to cancel your membership at any time, and once you've cancelled you will not be billed again in the future.
To cancel Vocal+, visit your account settings, scroll down to the Vocal+ section, and click the "Manage Vocal+" button. From there, you can click "cancel plan," and your membership will then expire at the end of your billing cycle.