No. If you have found a nanny and no longer require a subscription to CanadianNanny.ca, you are responsible for cancelling it, even if you are using HeartPayroll.com.
As CanadianNanny.ca is a self-serve service, it is the user’s responsibility to monitor their account and manage their subscription. You can always cancel your subscription at any time directly through your Settings page > Subscriptions & Payments > Cancel subscription.
Once you have successfully cancelled your subscription, you will receive a confirmation email with details on when your cancelled subscription will expire, and confirm that "no further charges will be applied."
For more information see, How do I cancel my subscription? and Where can I find your terms and policies?