How to cancel will depend on where you purchased your subscription:
Pocketmags.com: to cancel a subscription recurrence login to the site and
click hereApple App Store: instructions on how to stop an auto-recurring subscription bought through a title's branded app or the Pocketmags app for iPad and iPhone can be found
hereGoogle Play Store: instructions on how to stop an auto-recurring subscription bought through a title's branded app or the Pocketmags app on Google Play can be found
hereAmazon App Store: instructions on how to stop an auto-recurring subscription bought through a title's branded app or the Pocketmags app can be found
here