A complaint is an expression of dissatisfaction made to an organization, related to its products, or the complaints handling process itself, where a response or resolution is explicitly or implicitly expected.

ISO 10002 for quality, arrangement: customer satisfaction – Guideline for complaint handling in organisation is an excellent customer service certificate and acts as a ”true-to-life” manual designed expressly for this purpose. This standard helps organizations to identify, manage and understand how successfully they deal with their customers”