This research investigates the relationship between the types of complaint and triggers. We examine the fundamental question of do customers complain and if they, then under which type of trigger they complain more. Specifically, we examine mobile service provider, as services present a unique challenge for marketers. The human element of service delivery creates many opportunities for failure. In this research various sub-stages of the purchase stage of mobile buying process were identified and complaint responses at each sub-stage were studied. Qualitatively it was investigated that customer complaints were caused by which trigger at each sub-stage. Research results reveal compliant is caused mainly due to reactional trigger irrespective of buying sub-stage of purchase and situational trigger has least impact.