Below was reply received. From this it seems there is limit to number of failed transactions.
We understand that you are facing issues while paying your credit card bill.
Please note that you have reached the maximum number of Failed Transactions credit card and will be able to pay the bill in the next month’s billing cycle.
This is due to the monthly transaction limit set in place for the Freecharge users, which varies from case to case. You may, however, continue paying the bill for other credit cards.