Your subscription will auto renew for a new bundle of leads when you've used the remaining leads in your current bundle.
Once you've used all your leads in your current bundle, and receive the first lead of your new bundle, your subscription will automatically renew. At that time, the card listed as the default card in your account settings will be charged for your next bundle of leads.
You can always update your payment by using this link.
Here is an article on how to update your payment on the ptaform.
Tip: You'll receive a renewal reminder by email when you have 5 leads remaining in your current bundle.