SAA bad service

My experiance with SAA i was not happy at all with your service.i booked a flight friday which depart sunday at 12pm.On sunday i checked in hours before my flight which is flight no SA333 from or tambo to cape town. when i get there at 11:20 which is also my boarding time @ gate E2. i waited there was nothing no sighn,then i asked one of their assistant around 12pm she told me that i missed the flight how come?? and she also said that the boarding gate was changed. which is i didn't know.one of the managers said to me it was announced at 11:10 i was'nt therethat time. i had to pay for another one that depart @ 18:45 which delayed as well. you failed to communicate with me regardingthe changes of the gate which is not my fault but i had to pay. how can you announce such this what if i was deaf??? you send sms notification when we pay but you failed to do the same when you chanfe gates what happened to the batho pele prinsiples. IM FURIOUS ABOUT YOUR SERVICE.