User: A customer calls and has questions about the bill for their first month's subscription. They want to know why the monthly rate is $45.00, but the bill is for $60.00. What is the most likely reason for the bill being this amount? The customer owes a late fee in addition to the subscription amount. There was a mistake and the customer was over-charged. The subscription began about 10 days before the 15th of the month. The customer's account was upgraded to the next subscription level.