If you want Cancel Subscription then Open link : https://fizfy.onfastspring.com/account  , Enter email which you used during card Saved. Enter Email & Click on Continue Button. You will get email at inbox link to manage your orders. Check Inbox and Click on Link : Click here to manage your orders. When you Click There then you will reach at :

After Click on Continue Go to email inbox :

When you will click on Manage your Orders Page will reach at :

You can Cancel Subscription from here by Clicking on Button Active Subscription.

If you want Remove your Saved Card , Then Click on Tab Account Details and Payment Methods.Click on Manage - Remove

Your Payment Methods & Cards info will be removed. & You will not get Billed Further.