Rebook (Due to Covid) Nightmare.

I am very dissappointed. I had bought flights for 4 people from JHB to CPT in March Last year. This obviously got cancelled due to Covid. With a nte that I can rebook. Been trying all day to rebook the flight, only to find out it will cost me R10 000 more (roughly), Base costs, blah blah blah. I could litterally buy new tickets at a cheaper rate than the rebook. I find this completely unacceptable, and I am unhappy, as it feels I have lost the money spent. Will not be using Kulula again.