What happens when I cancel the automatic renewal of a subscription?

Immediately nothing. You can continue to enjoy the benefits of your plan until the plan period is over. When that time comes, you will not be charged for the renewal and you will lose access to the plan.

Please note that when you cancel the auto-renewal of your subscription plan you will lose access to all jobs created within the plan. Jobs marked as 'regular' that have been unlocked separately from the plan will remain open and accessible.