Kulula takes money worst airline

We booked for 9 o clock flight paid and when we get there they say the flight is over booked by 20% and there is 20 people on standby for 11 o clock flight and that they are over booked for that as well .take my money and no service what's my point of booking a seat for a certain time **** service with no solutions ... Never happened to me with other airlines telling me they can do this by law ....so taking my money and wasting my time