[Resolved]  BSNL Broadband — no proper metering system for data counting

i have bsnl broadband 'home 500 c' plan in which nigh 2am.to morning 8am free service of internet is available.credit for one mont exept night unlimited is is 1.5 gb and if further it is 80 paisa per mb.the prolem is when i connnect net on 2:05 am there clock is ten minute late and it count the units(data) in chargable.means it should be count only up 2'o clock for chargable units (as there clock is 10 minutes late) bu it charges me as follows;
1. when i connect internet at 2:05 am it conect actualy at 1:55 am
2:it should charge me only for 5 minutes (up 2 am)
3:but it charged me until i diconnect i.e 2:30,3:00 or 4:00 am
4 it give me bill of rupies 2800 insted of rupies 500 for the month august 2009
5.if night 2 am to 8 am is free then why they are charging me? are they cheating?
6.why there clock is set back 10 minutes i set my clock on TV so whitch is correct?