This study defines into outbound customer complaints arising from inventory variances at Apollo Tyres NDC1, with the primary objective of understanding and addressing the underlying issues. Through a secondary objective, it aims to identify root causes, assess customer impact, apply the DMAIC methodology, and evaluate improvement measures. Using a structured approach, the study examines factors contributing to inventory variances and their implications on customer satisfaction and loyalty metrics. By implementing the DMAIC framework, inventory management processes are systematically analysed to identify areas for improvement. Improvement measures, including macro implementation, wall-to-wall audits, and the proposed Outbound Integrated Optimization and Navigation System (OIONS), show promising results in reducing inventory variances and mitigating customer complaint.