All subscriptions are handled directly through iTunes.
There are several ways to manage your subscriptions.
Go to your iPhone Settings and tap your name at the top (it says "AppleID, iCloud, iTunes & App Store" under your name).
Tap on your iTunes & App Store.
Tap your Apple ID in blue at the top. (You'll be prompted to sign into your iTunes account)
On the popup window select “View Apple ID”.
Scroll down and tap "Subscriptions".
On the following screen tap “Crew Buddy”.
If you wish to cancel your subscription, tap "Cancel Subscription".
Or if you want to switch to monthly or yearly, you can tap the one you want.
You can visit the official Apple website for more information: https://support.apple.com/en-us/HT202039