Yes. Gliffy Online subscriptions/payments are automatically recurring unless cancelled before the Next Recurring Billing Date listed under your Account Summary. Users agree to this when they click "Purchase".
Admin users are responsible for cancelling their Gliffy Online accounts if they do not want to renew. This must be done before the Next Recurring Billing Date listed under their Account Summary. Gliffy cannot be responsible for charges incurred if the account is not cancelled before the renewal date. Gliffy does not send reminder emails as the Next Recurring Billing Date is always listed in the account.
To cancel your plan, please follow the directions listed here.