Apperently late for a flight

I booked to tickets for a Kulula flight 3 days ago. I pitch up at the airport an hour earlier only to get told that i cannot board the flight as i am late. This is a domestic flight which i am an hourly early for and yet still cannot get on. The counter clerk also has the worst attitude in the world and refuses to give her name and is not wearing a name badge. This is the worst service i have ever experienced and will never even look at Kulula again.