Karbonn Mobiles — PHONE CAMERA NOT WORKING AND APPLICATIONS OPENING VOLUNTARILY

I purchased Karbonn Titanium S5i online from ebay during March 2014. Phone is still in warranty. Its camera is not giving good picture despite claim of 8MP camera. (Picture is blurred and bad colors). While listening to a call, the screen changes and applications start opening on its own. Local Service centre says model S5i does not come in their system and they can't accept if for repair. How can I get it repaired.