ACME-3010: Bug for Billing Service reliability improvement 10

Date: 2025-09-09 Type: Bug Priority: P0 Service: Billing Service Owner: Revenue Platform GitHub References: GH-3010, GH-3011 API References: API-BILLING-01, API-BILLING-02, API-BILLING-03, API-BILLING-04

Business Context

Acme Commerce depends on the Billing Service to protect customer trust during high-volume shopping periods. This ticket captures engineering work needed after operational reviews found risk from out-of-order event delivery from the shared event bus.

Scope

• Review service contract behavior against API-BILLING-03.
• Update dashboards and alerts owned by Revenue Platform.
• Coordinate rollout with the teams that operate Authentication Service, Checkout Service, Billing Service, Inventory Service, and Notification Service.
• Link implementation work to GitHub items GH-3010, GH-3011.

Definition of Done

• Tests cover nominal, timeout, replay, and malformed payload scenarios.
• Runbook steps are updated and validated in staging.
• Incident review owners can cite this ticket as remediation evidence.