Flysafair Ripping us off during Covid

My wife had to change her flight due to her not feeling well. I requested a change of flight. The initial ticket was R1500. The flight we requested was R921 but I'm told we won't get a credit for the balance. Absolute ******* especially during covid. I was forced to request a voucher but was charged R300 penalty or admin fee. What a *******. I always booked British Airways as they gave me a full voucher refund with no fees due to covid. Flysafair is creaming the moola as they are the only ones flying and we have no choice due to our emergency. By choice I shall never choose Flysafair as they *******s . It's time for more competition