SAA not willing to assist

On the 14th of June we were supposed to board our flight to Mauritius on SA 192 we were held up at passport control and our flight departure was at 8:40 we got to the gates at 8:42 and the plane had already left. There was no boarding calls neither were there intercom calls to advise that they were awaiting us to board and it was our 1st time going overseas. We went to the ticket re-issue counter and Nicholas advised that he could re-issue me with new tickets for a flight boarding at 10:30 to Mauritius, however because the tickets were issued by Thompsons he needs to authorisation from his Manager. Marlene his Manager advised that they were not allowed to re-issue IT Fare tickets and that we needed to buy new tickets for the next flight. I contacted the emergency number for Thompsons and spoke to Janice who was very rude and she spoke to Marlene advising her that Lisa Bennett a Senior Manager said that in cases of emergencies when clients missed their flights SAA could re-issue tickets for the next available flight. Neither SAA nor Thompsons were will to assist we received rude and abrupt treatment and we were told by Thompsons and SAA that we must just calm down and pay the money