Bad service from Kulula

We had 2 return tickets JHB-George-JHB booked and paid in 2020. In 2021 they were not flying until around August/September and then we were told we have to use the tickets before the end of November or lose them. They gave us a credit of R2500. I tried to rebook the flights for October and was told that the cost was over R9000. So we booked for the same dates on FlySafair and paid for 4 day car hire for less than we would have had to pay in to Kulula. I think it very unfair to lose R2500 but it is better than pouring more money into a losing airline. Shame really as they used to be so good!