Standalone subscriptions you've purchased outside of Amazon Prime Video, directly from a subscription provider such as Hallmark Movies Now, are separate services and cannot be used within Amazon Prime Video.
Amazon Prime Video offers an individual Channel subscription to Hallmark Movies Now, that mirrors the content available through our Hallmark brand app. This type of subscription is entirely contained within and accessed exclusively through the Amazon Prime Video service; subscribed monthly, but not available annually.
To manage your Amazon Prime Video Channel subscriptions, including Hallmark Movies Now (if you have subscribed within Prime Video), you can go to Amazon.com and check under Your Subscriptions, rather than the Hallmark brand app.
For more assistance with how to access your Amazon Prime Video Channel subscriptions, please visit https://www.amazon.com/gp/help/customer/display.html?nodeId=201975120
You can also contact Amazon Customer Care at 888-280-4331 or via https://pay.amazon.com/us/help/202042890