Excesive battery drain on Existenz 3.5 due to... whatsapp?

My Z2's battery is draining really, REALLY fast. In a normal day I only use it to check whatsapp sometimes and mostly to hear some music.

I have Existenz 3.5 installed on my phone and I thought it might be rom related issue so I clean install a couple of times and nothing happened. Then, I checked on the battery stats and saw that the Whatsapp was the app that was consuming the most amount of battery (30%) then the Google Play Music (around 9%) and so on... So I decided to greenify Whatsapp... Still the same thing.

While all this happened I should say that auto sync was disabled, I was using 2G, the minimun brightness and barely turn my screen on.

After all this happened I decided to put the phone into Android's battery saving mode, still nothing happened. I don't now what to do, I also already calibrated my battery.

Is this soft-hard ware related problem? What should I do?

P.S.
I'll post the screen capture as soon as my phone wakes off it's dream.

Upgrade from D4 to... Samsung Relay 4g?

Does anyone had an experience with the relay T699? i've never had any close up experience with it since i'm in Brazil and probably will import from the US.
Does the relay is worth the hassle? i would put my D4 for sale since Blackberry will come out with a new android powered device with hardware keyboard and the relay seemed like a nice cheap device for a while. Or should i just wait and get a Priv?

Thanks!