Problems with android. OS sucking data.

[Anaximander]

maybe you got a virus or a faulty app of some sort installed. Have you tried installing an app to monitor bandwith usage to make sure android itself is the culprit? I'm no expert but perhaps there are apps that will give you info on which specific processeses that take up all that bandwith. those numbers you are listing are extremely high. I couldn't get near that even if my phone was the only device with internet access in my house.

You can try reverting the phone completely to manufacturer standard and then update it to whatever version of android you are running. I've had a couple of different version android phones for some time, and I had a lot of odd behaviour at times (system stalls, apps crashing) and doing a complete reset and re-update fixed things temporarily.