Issues on Dunning Setup

Summary:
Mentioned herewith are some of the blockers we identified during dunning setup implementation. Appreciate a response on the concerns.

Content (please ensure you mask any confidential information):

Hi,

We have identified the following key critical showstoppers when implementing dunning at our organization. Please assist in resolving these and to find a feasible way forward.

1. When sending dunning letters can few random customers be excluded rather than sending the letters to all customers?
2. Is there a bulk upload option available to update the customer master to enable dunning delivery, rather than manually updating the master?
3. Is there a possibility to automatically trigger dunning email delivery as soon as the ageing bucket of a customer is changed, rather than manually sending the emails?