Why am I charged the full charge price?

The billing period depends on the type of subscription plan that you chose. The information on the final amount is always included in the text on the payment screen before the subscription is confirmed. 

In brief, if you order a monthly subscription, you'll be charged once per month. If you get an annual one, you'll be charged once per year.

FYI: Monthly cost under our annual subscription indicates how much you save if you order a long-term subscription. Please keep in mind that you'll be charged more if you want to pay monthly.

The important step to avoid further charges is to cancel your subscription. You can easily do it by following this instruction, provided by Apple Support.

We, as a developer, do not have any access to users' payment details, nor do we conduct any transactions - they are processed directly by the App Store/iTunes according to the payment plan that was chosen through the payment method that is linked to users' Apple ID. 

So if you feel that anything might have gone wrong with the charge or your subscription plan, please reach out directly to Apple Support. Here are the instructions on how you can request a refund.

Hope this information was helpful!