You will be charged the full amount and the data allowance will also be given in full irrespective of subscription date.
You can keep track of your data usage using the three options below:
Your data will be consumed in the following way: first, your in-plan data allowance will be consumed, followed by the data allowance of any data pack you have purchased wherever available, and then the data allowance of your Data Booster.
Data consumed from a data package will be deducted at 30KB increments. To prevent customer from accidental data usage, Pay-as-You-Go data is blocked by default incase the Pay-as-You-Go Data is unblocked by customer, usages will be rated at 1KB pulses.