If you subscribed via our website, you can follow these instructions to cancel your subscription:
Go to qz.com and log in
Click on you avatar in the top right corner, and go to "Settings"
3. Select "Membership and billing" tab, and click on "Cancel your membership"
And you're all set!
If you subscribed via the app, then you are subscribed through iTunes, and have to cancel through iTunes:
Launch the Settings app on your iPhone
Tap iTunes & App Store
Tap on your Apple ID
Tap View Apple ID when the pop-up window appears
Enter your Apple ID password, fingerprint or face ID when prompted
Tap the Quartz subscription to cancel it