Market data fees are charged immediately when subscribing to the current calendar month. Renewals are charged on the first day of the new month. Both can be charged using a credit card or deducted from your trading account.
If you want to change your market data selections so you are not charged for a particular exchange next month, please do so anytime before the first day of the next month. Unfortunately, exchange policy requires that these fees are not refundable and are charged for the entire month, even if you only had access for part of the month.