Flipkart — Issue with phone exchange with flipkart

Today we had delivery of our new phone in exchange of old phone. However when the person came for old phone inspection (Wishmaster). He took around 15 minutes to check the phone and at the end he said ther is an issue of discoloration. Which he showed us in white screen. When we asked him to show same in other colour background. He said it is only can been seen in white background and the discoloration is also showing him white. I do not understand how any one can see white line in the cornor of phone in white background. He was not able to justify his issue. Are Flipkart making fool to customer. When i tried to connect with Flipkart customer care. They said as per policy, wishmaster has only authority to finalize. There should be some stict action will be taken against such person and company.