You may cancel your subscription by following the steps below.
Note: The subscription will auto renew annually or monthly depending on the option you purchased

iOS devices:
 
1. Open Meet Mobile app

  2. Go to  tab
  3. Go to Manage Your Subscription
  4. Click Track Meet Mobile/Meet Mobile Subscription
  5. Click Cancel Subscription

Or please refer to the link below to manage your account:
https://support.apple.com/en-us/HT202039

Android devices:

 
Important: When you uninstall the app, your subscription won't cancel.
  1. Open the Google Play app Google Play.
  2. At the top right, tap the profile icon.
  3. Tap Payments & subscriptions ---> Subscriptions.
  4. Select the subscription you want to cancel.
  5. Tap Cancel subscription.
  6. Follow the instructions.
Note: If you have a subscription with an app and the app gets removed from Google Play, your future subscription will be canceled. Your past subscriptions will not be refunded.

Or please refer to the link below to manage your account: 
https://support.google.com/googleplay/answer/7018481?hl=en&co=GENIE.Platform=Android

Note: If there is no Cancel Subscription button showing out after following the steps above, it means the subscription auto-renewal has already been turned off.