How do Amazon Music Unlimited Subscription Charges work?
At the end of the Amazon Music Unlimited trial or your chosen membership period, your payment method is charged for the next membership period.
Standard monthly and annual Amazon Music Unlimited plans follow a monthly or annual billing cycle based on when your subscription begun.
Amazon Music HD subscriptions follow a monthly or annual billing cycle based on your Amazon Music Unlimited Individual or Family plan subscription.
Once the free trial period associated with Amazon Music HD ends, your payment method is charged.
If you upgrade to Amazon Music HD two separate charges display in your account. One charge for the Amazon Music Unlimited base subscription and an additional charge for the HD subscription.
The billing cycle depends on when you started your Amazon Music HD subscription and the free trial period associated with each plan.
For more help, try our Amazon Music forum