SAA - Refund issue - gate closed prior to 15min cut-off and charged as no show

Closed the gate early and called me a no show - i was at security a few minutes before gate closing and my ticket was scanned as invalid - they had already closed the gate BEFORE the 15min cut-off time - hence my ticket showed invalid at security - i had checked in the night before and they had my number and still closed the gate early without me - even though my ticket didnt scan they let me pass and I arrived at the gate exactly 15 min before and i watched them remove the stairway to the plane and they told me the pilot was taking control - if it was only now 15min before and they were already removing the stairway this reinforces that they closed early - contacting the booking agent who contacted the airline and was told that they rejected my refund as i was noted as a no show - i have escalated the matter and requested logs of my ticket being scanned at security showing as invalid was before the 15min cut off time

I had to book another flight with FlySAFair and they also had a lady which they were waiting for - they repeatedly called for her on and off the flight and waited an additional few minutes for her as i assume she already checked in - i hoped for the same courtesy with SAA and was not shown this - instead SAA did the opposite and they purposely left me behind to have the flight leave a few minutes early