To cancel any Zyro subscription, all you need to do is deactivate the auto-renewal option and let it expire.
To do so, complete these three simple steps:
Go to your Subscriptions page
Find the service in question
Turn the auto-renewal option off
The service will remain active until its expiration date, and after that, it will be canceled:
NOTES:
The domain renewal fee is charged 30 days before the domain's expiration date in order to ensure uninterrupted domain service; if you decide to cancel your domain name, make sure to disable its auto-renewal by then
Learn more: Terms and Conditions, Refund policy