You can downgrade and cancel reoccurring billing at anytime. Login to your Tagboard account and select the account icon in the top right corner of the page. Then choose Account Settings from the drop down menu.
From your account settings page, open the billing tab where you will find a "downgrade to free" button. Simply select this button to cancel your subscription.
If you'd like to delete you Tagboard account, please reach out to firstname.lastname@example.org with the subject line: "Account Deletion Request".