You can cancel your subscription anytime. Depending on how you signed up, you can cancel inside the YOMU app or from inside the subscription settings on your Apple device.
If you subscribed through YOMU directly:
Tap your user icon on the top left of the screen in the app.
Under Account >> Subscription management >> Manage Subscription >> Cancel Super
Cancellation stops future renewals, but access continues until the end of the paid period.
If you subscribed through Apple:
Go to Settings on your Apple device
Under Apple Account select Subscriptions
Choose YOMU and tap Cancel subscription
Cancellation stops future renewals, but access continues until the end of the paid period.