Premium is billed by Apple or Google, so you cancel or change it in their subscription settings. Castria has a shortcut: Settings → Change plan.
- From Castria: open Settings. On your Subscription card, tap Change plan, Payment method or Billing history. Each opens your store's subscription page, where you can also cancel.
- On iPhone: open the Settings app, tap your name, then Subscriptions → Castria.
- On Android: open Google Play, tap your profile picture, then Payments & subscriptions → Subscriptions → Castria.
When you cancel, Premium keeps working until the end of the period you've paid for. After that:
- your smart playlists stay, but you can't edit them;
- your cloud storage becomes read-only.
Skipping ads on your phone keeps working for free.
If you subscribed on one kind of phone and now use another, manage the subscription from the store you paid through.