If you have created the membership via iTunes, you must cancel your membership via the Apple ID under which the iTunes subscription was created - it may be a good idea to go through all the Apple devices in the household.
You can follow this guide on how to cancel the membership on your iPhone or iPad:
Open the Settings app on your iPhone.
Tap your name, then tap Subscriptions.*
Tap that Maneno subscription.
Press Cancel subscription.
*If you don't see "Subscriptions" under Settings, tap "iTunes & App Store" instead. Tap your Apple ID (usually your email address), then tap Show Apple ID. Log in, scroll down to Subscriptions, then tap Subscriptions.
If necessary, see the full instructions from Apple here, where you can also see how you can cancel the subscription from PC or Mac: AppleSupport
If you want to cancel your membership via credit card, you will find instructions in the article: How do I cancel my membership?