Here is a troubleshooting excerpt from the article on Differences between iTunes and website subscriptions.
Troubleshooting Playback/ChartBuilder In-App Subscriptions
Are you encountering issues redeeming your Apple App Store subscription(s) for ChartBuilder or Playback? A common fix for issues caused by expired billing, late payments, etc. is to Restore In-App Purchases.
If you have an active Apple Subscription, it will be displayed either on your "Subscriptions" page with the 📖Apple App Store, or on your 🌐MultiTracks.com subscriptions page.
Playback: Restoring In-App Purchase
Log into Playback on the iOS Device with the Apple ID subscribed via iTunes
Navigate to Settings -> About
Tap Restore Purchases
Log in to your Apple ID
ChartBuilder: Restore In-App Purchase
While looking at the chart view, Tap the More menu in the top left
Tap the Account icon to open account settings
Tap Subscriptions
Tap the "Restore In App Purchases" action at the bottom of the subscription options.
Still encountering issues with an App Store in-app purchase? Please reach out to us using the chat icon in the bottom right of your browser and we'll be here to help!