Why is my bill lower than it should be? Your bill is based on your sign up date. If your sign up date falls after the billing cycle begins, your subscription fees, minutes and data for that month only will be prorated. This can be seen on page X of the bill – Monthly Subscription Charge. Related articles Why is my bill higher than expected? What happens if I don't pay my bill on time? How to insert your SIM What is my billing cycle?