Objective: The objective of the developed inventory model is to find the optimal solution for the retailer, while performing inspection for the defectives, and also to offer partial credit periods, where shortages are allowed. Methods: To derive the required solution which benefits the retailer, the partial derivatives method for the decision variables where used and to solve the complicated differential equations the necessary and sufficient conditions has been derived and the theorem and its proofs are given. Findings: In this research findings, the optimal credit period policy and promotional effort dependent demand pattern that offers more profit to the retailer, provided with inspection policy for finding defective items in the lot. Shortages are allowed and completely backordered. Numerical examples and sensitivity analysis are performed to verify the reliability of the developed model. Novelty: This study presents a new model wherein the retailer offers credit period and with shortages that will apt the real life situation as the model developed here is for deteriorating items, which is inevitable to maintain the perfect system. Keywords: MultiEchelon Inventory Model, Sustainability, Shortages, Credit Period Offers, Learning In Inspection