You can cancel anytime via your account portal, there are no lock-ins or cancellation fees.
Once you have logged in, simply scroll down on your subscription homepage and you'll see the option to cancel:

We're really sorry to see you go, so if there's anything we could be doing better, we'd love to hear your feedback. Just drop us an email to hello@gethumantra.com.
Please note, if your subscription just renewed, it will likely not be possible to cancel your most recent order but you are welcome to return it for a refund provided it is unused and unopened.