Xiaomi — Mobile phone issue

Address:

122001

I have purchased MI 4I on 15 OCT 2015 .Before it got some technical issue and it was not getting charged.
I went to service center on 2 July 2016 and they promised me return it within 10 to 25 days at max.Now they are not taking my call.And i went to store to take my phone back ...I have to wait there for 4 hours but still they are not giving it to me.Kindly take some action in the same .

Complaint NO./Job sheet no. is wxim[protected]