A customer calls and has questions about the bill for their first months 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

Most billing cycles are processed by a company at the same time each month. The reason for the increased bill was the customer began the service after the last monthly bills were sent out, so by the time the next monthly bills were sent out, the customer had incurred half of one month and the full next month; hence the increase in the monthly bill.