Lenovo — Faulty screen buttons

Address:	Patna, Bihar, 800001
Website:	lenovo.com

I had purchased levovo k50a40 smartphone through flipkart.com on 8th feb 2016. It screen buttons aren't working from 3rd april after approx two month of purchase.
I have made chats with lenovo support through its site lenovo.com. It has been shared that imei detail isn't available with lenovo and also advised to send image of imei and invoice copy to [protected]@lenovo.com. I have sent detail of imei image and invoice copy by mail on 6th april 2016. It has been replied that "lenovo india sppop registration team regret to inform you that as per the imei number mentioned in the invoice copy, we were not able to update the warranty due to a validation error". Lenovo india sppop registration team advised to send details to [protected]@lenovo.com. I haven't receive any appropriate solution after mail.
Due un-registered imei number i am unable to take services regarding warranty.
Please do the needful for appropriate solution regarding warranty or exchange of mobile set