Xiaomi India — No response from the company

My mobile is in the servicing centre for over 3 months. I got the mobile in march from flipkart. But after a few months I found a problem. The problem was that the mobile switched off automatically. So we handed over the phone to the servicing centre in bhangaghar, guwahati on 5th july and they said that the motherboard was bad. But today is 5th of october and till now the mobile has not yet come. Its over 3 months we have bern waiting. So I please request you to look into the problem and send the part as soon as possible