If you signed up for Prime Video through your iTunes account and later signed up for Prime with Amazon, you may be paying twice for Prime Video benefits.
To resolve this issue, you can cancel your Prime Video membership from the Apple website. This will keep your Prime benefits (including fast delivery at no extra cost, Prime Video, and more).
It can take up to 7 days for Apple to process a cancellation. If you have already cancelled your Prime Video membership, no further action is needed.
To learn how to end your Prime membership, go to End Your Prime Video Membership and adjust your membership settings.