From within the Confide app, go to Settings > Confide Plus > Manage Subscription, and tap on Confide to manage or cancel your Confide Plus subscription.
If you cancel Confide Plus, your account will automatically revert to Confide Basic (the free version) after your subscription expires. So you can continue using Confide for free.
For additional information about subscriptions, please refer to the support articles provided by Apple for iPhone/iPad or Google for Android.