Hello, buddy: Your situation I 5700 also have, there are two arrows below the battery that is always connected with the network, but also very power consumption, if you do not open the monthly GPRS, the cost is amazing, you click \"exit\" from the Internet from the mobile phone, the arrow under the power supply is not, indicating that the network is disconnected, it is OK, as for other charging items have no, Give customer service or business hall contact is also better to solve, well, I wish a happy life!
The bill has nothing to do with the mobile phone, you can only go to the operator to check the bill, the most likely reason is that your traffic exceeds, because 6 is to support 4G network, if your traffic is only dozens or hundreds of megabytes, click on a circle of friends video will not, see a few more will certainly exceed...