Flight delay

On 23/6, i was supposed to depart at 08h45 to OR Tambo from Harare. We were notified that the flight was delayed to 19h45. Upon arrival, we were booked in and our ticket suggested that we will depart at 17h45. No such luck. The flight did not even depart at 19h45 as re-scheduled. We finally departed at 21h00 on a different carrier from the domestic terminal. No staff to advise us, appologise or even inform us about the resons for such a lengthy delay. Its the last time that I fly with this carrier.