Motorola — Motorola MOTO G(2nd gen) damage piece

I am Raj shah and I have purchased MOTO g2 from flipcart in October and that was damage piece in which one sim slot is not working..I had exchanged that phone and I got new ph of same model in November 2014..but I have serious issues of heavy network fluctuations... I had visited 2 service centre of Motorola in this one month..they both had done software reinstallation...still problem is as it is..another problem is its early battery discharging...both problems are giving me headache now...what to do ??.. Phone is in warranty..order id is OD[protected].