Xiaomi India — violation of warranty

Address:

Jaunpur, Uttar Pradesh, 222002

Jaunpur service center kept my phone more than 50 days and won't repaired the phone. When i complaint customer care they told your device is out of warranty. They used to close the jobsheet without my permission too. I had submitted my final jobsheet on 28/sep /17 but warranty is upto 15/sep/17. They had not repaired the phone properly, when i insist they said its out of warranty now.
The customer care also not provided any proper resolution i keep on mailing. Due to delay in response by them. Now they also told its out of warranty and making excuses why had you collected the phone. Earlier they used to called and said"sir apka phone ban gaya hai jakr leliye" jab leliya tb bol rhe hai out of warranty ho gaya.
I checked infront of their engineer too they told "ab kya kre sb to badal diya, isse koi diwqat to ni hai" hadd hai.