To cancel an iOS track-pack subscription, follow these steps:

1. Launch the Settings app on your iPhone or iPad.
2. Tap on iTunes & App Store.
3. Tap on your Apple ID at the top.
4. Choose View Apple ID from the popup menu.
5. Enter your password if/when prompted and tap on OK.
6. Tap on Subscriptions.
7. Tap on the Mad Skills Motocross 2 subscription.
8. Tap on "Cancel Subscription" at the bottom. 
9. Tap "Confirm".

To cancel an Android track-pack subscription, use one of the following:

• On Android, open the Google Play Store, then tap Menu > Subscriptions. 
• On a computer, go to play.google.com, then in the left menu click My  subscriptions. 
• On either Android or a computer, use the URL  http://play.google.com/store/account/subscriptions to open your list  of subscriptions. 

You  will get to keep all tracks you've downloaded during your subscription period.