To cancel a subscription you will need to login to your account -- How to login to your account
Once in your account open the "Subscriptions" tab and next to each of the products you are subscribed to you will see a "Cancel" button.
Clicking this will cancel your subscription to that particular product.
How to login to your account
You can login to your account by going to this page
If you need to create an account your login email should be the same as the one used when you setup your initial subscription.
This ensures all of your subscription's details will be available to view and modify.