Xiaomi India — about not working properly

Address:

848504

I bought my phone 6 month ago. From that time only it is not working properly. It problem is that, in a day at least two time i have to close the mobile. Because no call is going and coming. I think it is due to the problem of mobile. So what can i do, please resolve this matter. I don't no where is service center or not. And i listen that it is taking money also in service center. So kindly accept this problem and please resolve it.
Thank you