First and foremost, my deepest condolences..
I had a similar occurrence on my local set about 2 weeks back. This unearthly possession of the phone is rather a rare phenomenon. In my case, I had exerted more than the usual force on the screen while attempting to put it into the spigen slim armor case. I was so sure that my screen was a goner but by some divine intervention, after 5 minutes or so, it started operating normally. My G2 had a even more bizarre episode. That beast of a phone got possessed too and it did not end well for it. The screen just died after suffering for 3 days. Saving grace was that the warranty was on its last legs and LG replaced the mamaboard and screen for me after which, I sold it off.
Now, your only hope is contact the supplier whom you bought it from see if he can assist otherwise, bring it to a 3rd party handphone repair shop. There are many in Sim Lim and few at Bugis as well. Personally, I have ever patron the services of such a shop in Bugis for my Note 2 and the folks there were kind enough, to troubleshoot for me FOC. Price wise, they are about 200%-300% cheaper than the authorised service centre
Anyway, I wish you well.
