Unfairness of my flight voucher

Hi i bought a plane ticket to Capetown in April this year through Flysafair. My ticket was cancelled due to the pandemic in the world. So their policy was two options.Cash voucher for flying or a cash back into your bank account.Now i rate this airline company as pathetic.They are responsible for cancelling my flight.Now i requested a cash back voucher but with a charge off 45 percent off of my own flight money.I have been sending dozens of emails to the airline company but i have recieved no joy Its now more than 28 days that i await tje return of my money and still the company is adding a 45 percent tax.This is not fair i have asked to speak to a supervisor or management but they just giving me sad stories of their policies that they follow.I understand every company has their policies and terms and conditions. This is really not my fault and i expect a full refund of 844 zar . Thanks Mr Jl fynn