Bad services by Kulula crew and staff at O.R tambo Internaational

Bought a ticket to Durban for flight MN633 Saturday the 28th February 2020 16:15pm departure O.R Tambo, the flight was delayed to 16:50pm, we arrived at gate C10 at 16:38pm and the crew informed us that the we have been offloaded and the flight has left and the board was still saying final call for flight MN633. We than went to the customer service desk arrived at 16:45pm and they said to use that there was a mistake with the boards on changing of flights, we were not assisted, furthermore when they called the crew the flight was only leaving at 16:50pm. we then informed the customer services consultant that the crew said the flight left but now when she is talking to the customer services colleagues the flight is only going to leave at 16:50. we missed out flight and it was not our fault, the airline did not take and actions and did not apology's due to their error caused by their crew and staff & we heard to book another ticket to Durban which caused an inconvenience .