Walkies has two ways to subscribe:
Via Apple
Via Stripe
Tap here on your iPhone or iPad with the Walkies app installed it will take you to the "Subscription" section of the app. Or navigate to the subscription section by opening settings and tapping "Subscription".
From here tap "Manage subscription".
If you have an Apple subscription:
This will take you to the App Store.
Scroll down and you will be able to see a "Cancel subscription" button.
Tap this button to cancel your subscription.
If you have a Stripe subscription:
It will open a webpage in the app with all of your Stripe subscription information for Walkies.
Within this page you will be able you cancel your subscription.