kulua advertise one price and charge another

After spending most of the day searching for an affordable flight from Joburg to Durban for one night. Kulula are the winners......until we try to book and pay online. Nope wont work phone Kulula speak to a unhelpful Nicole to be told oh no the flight has gone up and that's why. I then log onto Kulula.com imagining that it would be updated, no its still says the same price. I then phone them again, hello Nicole..... who insists that I must be wrong. I ask to speak to a supervisor... surprise no I must deal with Nicole. Hence I got nowhere. I am disgusted by the way I was treated and the fact that they get away with ripping people off.