Mango airlines - refund for flights cancelled during lockdown

Hi I have refunds owing from Mango Airlines for flights booked during the lockdown. The issue is that Mango kept on taking bookings and then cancelled filghts with amending their vouchers and do understand that was not in their control. However they should have a plan to refund monies due to the nature of lockdown. I phoned the call center and followed up. The agent told me she will have it done in 48 hours. Its been 4 weeks now and I had to follow up again on the vouchers. Please can I have a full refund of my flights as it unlikely that I will fly for a value of R2400 within this year.