Scope

What are the scenarios in which dunning works without a card?

What are the parameters that Dunning requires if there is no card?

Solution
a. If you have Online Dunning enabled,  it is applicable only to those customers who have a payment method on file. Online Dunning settings are applicable to those customers who have an online payment method on file. Here is more on online dunning.

b. If at the time of renewal of a subscription; if there is no payment method present, and if the subscription level auto collection is set to on, the subscription will automatically be canceled with the reason - No Card. This is the hard-coded logic at our end, and this behavior cannot be altered. 

If a payment method is ABSENT from the customer/ subscription record at the time of activation or renewal, you need to ensure that the SUBSCRIPTION LEVEL AUTO-COLLECTION IS OFF; to avoid the automatic workflow we have in place (as explained in the previous email). 

Subscription-level auto-collection takes precedence over customer level auto-collection, and hence subscription level auto-collection has to be set to "off" as shown here.

c. If you wish for dunning to be applicable even for those customers who have no payment method present on file (provided that subscription level auto collection is set to off to avoid the automatic cancellation flow, as explained above), you need to ensure that you enable Offline Dunning settings within Chargebee, as detailed here.