KULULA: CAN'T CHANGE A FLIGHT

My son is booked on a Kulula flight that has to be changed. One cannot change a booking online with Kulula. This is unbelievable. Obviously they are behind with the technology. But it gets worse.... Kulula's call centre do not answer the calls. This, despite the web site saying that the call centre has to be contacted in order to change a flight. Does Kulula expect the public to forfeit their flights and pay for new flights that must then be booked? Shocking. Pathetic service.