Vaya will charge you one month in advance plan access fee on ordering your new Vaya service. The Vaya bill is based on a calendar month (1st day of the month to the last day of that month) but you will get get the full inclusions for the month, including all call and data allowances. A pro-rata access fee for the first month based on the number of days you are connected. For example, if you join on the 15th day of the month you will pay a pro-rata rate for the amount of days remaining in that calendar month and a month in advance but will still get all the call and data inclusions for that part month.
Vaya will automatically charge your nominated credit card that you used to order your initial sim card each month by automated direct debit, there is no need to manually pay your monthly invoice each month.