Whenever we got a quality complaint and claim, we need to provide a reasonable explanation to the buyer of how and why it happened. To provide this explanation, we need to make a thorough investigation to find out the possible root cause as well as provide the correct action plan to avoid future happening. During the investigation, we need to involve a lot of data and questions. In our past experiences, we spent a lot of time back and forth emails to collect the data and find out the root cause because either we forgot to check this or that.