A customer wants to return merchandise Store policy is that the merchandise cannot be returned what should you do?

Apologize saying "I'm sorry was there anything wrong with this item?" it may just be a simple fix or guidance that is needed and they may decide to keep the item, if not try to find what you can do for the customer maybe give a discount on another item, offer an exchange, a coupon , or a store credit. If you can not do any of the above then explain explain the reason for the denial of the return not just the policy. Usually there is a good reason the policy exists find out why and explain it in plain english and always make sure to empathize with the customer be calm but be assertive.