Question about payment on wireless account being 3 days late

Was wondering I have a payment pending for August 31st. My bill is due August 28th. I want to make sure that I won't have service interruption due to it being 3 days late. Will this be a problem? My wife is a teacher and she gets paid the last working day of the month. I normally make partial payments weekly to keep this from occurring however I did not this month because I failed to turn on my reminders in my calendar.