Your billing starts on the day your pack is activated. The validity period for all packs is 30 days. If you start your options base pack subscription of Rs. 99 in the middle of the month, lets say on 18th of June then you will be charged pro rata from 18th June to 30th June for 13 days which is Rs. 42.90. From July 1 you will be charged the full Rs. 99 per month. See illustration below

Activation DateBase Pack / Value PackSubscription AmountBilling DateValidity periodNo. of days left in the month* Billing amount
20/09/2016Infinite Futures Plan7991st of every month30 days11293
20/09/2016Infinite Options Plan991st of every month30 days1136
* Pro-rata billing is calculated as (Subscription Amount / Validity Period * No. of days left in the month).

The billing happens on the 1st of every from the second month. 

Your subscription will be active as long as your SMP  / Trading Ledger has sufficient funds to debit the monthly billing amount. If there is in-sufficient balance then the billing would be temporarily suspended and your plans would get suspended or de-activated. The moment you transfer funds into the trading / SMP ledger automatically the billing amount for that month would get deducted. Read more