PE airport worker refused to let board the flight

On 31/01/2022 I was supposed to catch a 14:20 flight with Flysafair yesterday from Port Elizabeth. I got delayed because of an accident that happened between Cookhouse and Peterson. The gentleman who was at Gate 12 closed the gate whilst I was running towards the gate and he refused to open for me although I had explained why I was late and begged. He refused to let me in. The flight didn’t leave for at least 15 minutes after I got there. In my opinion I would have still been able to get into the flight.

I went to the Flysafair helpdesk and asked for assistance, I was told that I needed to take the following day’s flight but that was impossible because my appointment in Cape Town was at 11am. I also couldn’t get a refund or anything. Kindly assist on how I can deal with the situation.