FuelCloud's services are charged on a monthly basis. Your billing date is based on the day you activate your first FuelCloud hardware. If a month does not have your date--you first activated your hardware on the 31st, for example--you will be billed on the last day of that month.
If you prefer, you can prepay for future subscription charges. Adding funds to your Prepaid Balance will charge your Default Payment Method in the amount you choose. Future monthly subscription charges will be paid from this prepaid balance until it reaches zero.
If your Prepaid Balance doesn't have enough funds to pay your subscription, your Default Payment Method will be charged the difference. Prepaid funds are non-refundable.