Evaluate Kill Bill with a subscription scenario that includes signup, a plan change, failed payment, retry, credit, cancellation, and reactivation. Check the account timeline, invoice lines, and payment state after every transition. Compare results to a written billing policy, not a demo screen.
Also test the gateway and tax integrations your business needs and decide how operators will resolve exceptions. A billing platform earns trust when every charge can be explained, corrected, and reconciled without silently rewriting history.
Akousa