NOKIA/ E71
Vanishing of software

I have purchased new E71 mobile from nokia priority dealer, sapna sangeeta road, indore (MP).

after one day of using it menu key started unworking until i restarted the phone. and all of sudden all the data and software from installation file get vanished.

customer care parsonal are saying that they dont have the key to this software. what should i do. this phone cost me dear. i want the worth of my money. please install the software or replace my phone.