Mivi.in — Mivi duopods m20 warrenty claim and not got back

I have purchased Mivi duopods m20
from Flipkart but I was not satisfied with the sound quality of the product even mic was not working up to mark normal calls i am not able to take my voice is not going to the person and while listening the music its sound is very very low so claimed the warranty I mailed them and they arranged a pickup they picked the product and got the mail that product has been reached and they are checking on the same and still I haven't got any reply nor my product i have mailed several times but I am not getting any response on the same I am attaching the mails ss and the guy who picked up the product