Gross Incompetence!!!

I was inconvenienced by incompetence of Mango Airlines who over-booking flight JE536 from Port Elizabeth to Johannesburg on Sunday, 9th September 2018. I arrived on time at the airport and found that the flight was full because it had been overbooked. I tried to explain to Team Lead Rashqua Gabriels that I had a connecting flight to Swaziland in Johannesburg at 4pm- so I needed to leave. She refused to assist only saying "sorry maam, the flight is full." There were about 12 of us who did not make it on the flight. The others got on a later flight leaving at 14:20 delayed by 20 minutes. I could not get on the flight since I would not make my connection to Swaziland. I was forced to spend the night in PE, which is not my home destination- sleeping on the couch at a friend's house. I eventually left PE on Monday, 10th September 2018 at 08:25hrs. Needless to say I missed my connection and ticket on the Airlink flight to Swaziland . I had to get a bus from Johannesburg to Swaziland. I had buy the bus ticket myself. The Team Leader refused to compensate for the inconvenience and just said she was sorry. I was really troubled and no one in Mango cared!!!!! Overbooking a plane and just apologizing for the inconvenience is gross incompetence!!!!