balance deduction in Reliance mobile

My Reliance connection number is 8103887969. My data pack is validate till 23/09/2013. and I keep it on till 3:30 am on 24/09/2013. I got an message from Reliance that my data usage in this duration is 91 kb, according to their data rate (10 paisa/ 10 kb) charges should be 1 Re. But they deduct my balance by 45 Rps (1 Re/ 2 Kb). Customer support is unsuccessful in providing me detail about how much data I used. They tried to convince me that they must have deducted the correct amount. I feel helpless in this matter, normally whenever Reliance charge any nonsense amount their customer support return that with an apology. Please look into the matter.