Unexplained Reservation Cancellation

Whilst on a delayed flight from Singapore to JHB I enquired via the website whether I could cancel or amend my onward booking from JHB to CPT in case I arrived too late. The FlySafair website informed me I couldn't cancel or change it and so, when I landed I ran to Domestic to catch the flight only to find it had been cancelled by FlySafair and I had to watch as the flight took off. I then had to buy another ticket as they told me I was a 'no-show', even though I was clearly there. I rebooked on Cemair as I refused to give business to a company that treats customers so badly. I have since tried to contact them via their "help" e-mail address and they have yet to even reply. Finally, I found out that they unilaterally cancelled a flight of a colleague of mine the same week.