Hello Hecberrones7,
Welcome to the community!
You should be able to adjust the phone's data cycle to match your billing cycle. You should be able to do so by Settings --> Data Usage --> click the dates (orange arrow below) --> Change Cycle.
Under the data settings, you should also be able to set mobile data limits by dragging the limits to your desired setting.
You should note that there usually is a slight discrepancy between the amount of data as determined by mobile devices and that recorded by the providers. The discrepancy is due to the different methods of measuring data: devices measure received data; providers measure sent data.
Hope this helps 
Cheers
