Why rely on reliance. Before disconnecting u can check how much you used. Since it shows in bytes, add received and sent then divide by 1024*1024 ie.1048576 bytes will give how many MB you used. I am using this and all calculations made in EXcel worksheet for the last 5 months. There is only a difference of 2% which is in favour of me. And I can use about 980 MB for each month for the last 5 months. For this you have some patient.