If you have decided to cancel your Kindle Unlimited or Kindle+ subscription, you will need to use a web browser on your mobile phone or computer to go to the Amazon service management page. If you no longer wish to pay or see value in Kindle+, follow the steps below to stop future monthly charges.
If you cannot find the option to cancel Kindle Unlimited after visiting the Amazon subscriptions page, it is possible that you subscribed through the Play Store on your mobile device. In this case, you need to go to the Play Store subscription settings and find Kindle Unlimited or Kindle+ among the active entries to cancel the service.
It is not possible to cancel Kindle+ (Kindle Unlimited) directly through the Kindle device itself or the Kindle reading app. However, you can use your mobile phone with the installed application to perform the cancellation via a web browser.
It is important to note that the cancellation is not immediate. Books you borrowed under the Kindle+ subscription will remain available until the end of the current subscription period, meaning until the next billing date. After this period, the books will be automatically returned. Books purchased separately will remain in your library regardless of Kindle+ subscription status.

