Consumer Redressal

I have Standard Chartered Bank\'s Manhattan Credit Card. While spending on the card, I overshot my limit. If I overshoot the limit on my credit card, the transaction should not be allowed. But in this case, the transaction was allowed and then the bank has charged me Rs 500 for crossing the limit. This is totally against the rules. What further course of action and what compensation can I claim from the bank in this regard as I already have paid my bill since I had to continue using the credit card.