Zen Mobile — newly bought but cant able to hear the voice of the caller

Address:

Chennai, Tamil Nadu

I bought Zen mobile ZEN U 105 FIREFOX ON 01/06/2015 . The issue is while speaking through mobile, the mobile got heat and also cant able to hear the voice of the caller .Touch is also not working properly.It has been just 12 days from the date of purchase, but i am facing these many problems.kindly replace the set as soon as possible.