@mg2017 I'm a bit late, but If your dunning requirement isn't so complex, you could build a dunning facility through a workflow and saved searches. @Matt you built this before. 30, 60, 90 day saved searches based off the overdue balances on the customer record, triggers workflow to send email with a specific email template that includes the statement.

hey @Paul Prystawsky thanks for the suggestion. I will consider your approach