Not providing refund for wrong color and faulty android phone

I ordered a Xolo Cube mobile phone from ShopClues. They provided me a Black colored phone, instead of my preference (Gold color). I decided to ignore it and proceed further with the Black colored phone. But during unboxing and first use, it turn out to be a faulty model. The econdary camera gets heavy grains while using phone for some minutes (soon as it gets heated up). I reported this issue to ShopClues within 6 days of delivery. As per their return policy they would provide return for issues reported within 10 days time. Now they are simply rejecting my return request without even providing a reason.

Friends, please tell me how to approach this situation…