Subscriptions are managed in your store account:
Android (Google Play)
- Open the Google Play Store app.
- Tap your profile picture (top right).
- Go to Payments & subscriptions → Subscriptions.
- Select your 2nd Line+ subscription and follow the prompts to cancel.
iPhone (App Store)
- Open Settings and tap your name at the top.
- Tap Subscriptions.
- Select your 2nd Line+ subscription and tap Cancel Subscription.