All subscriptions are handled directly through iTunes. Apple doesn’t allow us to modify your subscription. Apple requires that’s you do it yourself. Don’t worry though, it’s easy!
There are several ways to manage your subscriptions.
The easiest is to just click this link: https://apps.apple.com/account/subscriptions
Or the manual way of doing it is this:
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".
You can visit the official Apple website for more information: https://support.apple.com/en-us/HT202039