stinking attitude from staff

i was supposed to be on SAA flight SA23 from Harare to Johhnesburg on the 27th December 2015 departing at 12:50. i was at the queue from 12:00 to check in. when i got the front i was told the flight is full as it was OVERBOOKED. i was told to go to inquire about the next flighg. i went to see Mandy she accompied me to the man at the check in , Mandy ask the man in Shona what happenening why is the full, the man responded also on Shona tell her that i arrived at 12:40. i can understand a little bit of shona, but the fact is they should have spoke in English as thry are at.work and i.was there as the customer. there is lack of professionalism and they.were rude also. they placed.me.on flight SA29.departing 17:30. this was quite am incovienience financially as i.had to book to a hotel in johnnesburg and only came home to my family today. i am quite disappointed and also being patriotic amd flying SAA. you have lost a customer, BA is my flighg of choice from now on.