You can cancel your subscription anytime from within your account details -- without penalty. Click on your profile icon in the top right corner of your LANDR account, then click on 'Account settings' and then on 'Manage Your Plans' in the Subscription section.
You’ll see the 'Downgrade plan' button underneath your plan details to the right.
Click on it and complete all of the cancellation steps until the cancellation is confirmed.
If you cancel, your plan won’t renew the following month or year but you’ll still have access to your plan until the end of the period you paid for.
Keep in mind that if you have a discounted subscription rate, you’ll lose that price if you cancel your subscription.