recharge problem

[mayank1200]

i hv recharged my Tata Sky account online with a recharge of 500 ....i hv 2 sets..that makes Rs.400....so i shud hv 100 in my account.....its showing that the due date is 12th aug .at the time of recharge they showed tat the balance in my account is 500 bt now even though i hv charged my account they are now showing 485.58.y r they doing this?