Dabble makes it as easy to cancel your subscription as it is to subscribe.
Click on your account menu (your name at the top of Dabble)
Select Billing from the menu
Click Cancel Subscription at the bottom of the billing dialog
Once clicked, your subscription will be canceled at the end of the billing period. If this is not what you want, ask support to take care of it sooner.
Select Billing from the account menu
Click Cancel Subscription
You can also "undo" the cancelation if needs be