If you purchased your subscription via the iTunes App Store, you can check the status of your subscription on your iPhone by following the steps below:
Go to Settings on your iPhone
Tap Your Name at the top of the screen
Find the Dipsea subscription
Use the options to manage your subscription: Choose a different subscription option or tap Cancel Subscription. If you cancel, your subscription will stop at the end of the current billing cycle. If you don’t see Cancel Subscription, the subscription is already canceled and won't renew.
If you're being charged for a subscription, but don't see it in your list of subscriptions, make sure that you're signed in with the Apple ID with which you originally subscribed to Dipsea. If this is the case, you may also have purchased your Dipsea subscription via the Dipsea website rather than the App Store. Learn how to manage your subscription on the Dipsea website here.