Kulula

We booked a flight on kulula,but had to cancel it due to the Lockdown. kulula told us that they won't refund our money,but they will give us a Voucher that will be effective for a year,However a month has passed with no further correspondence from kulula.I assume many people may be in the same situation. It is very difficult to get through to them telephonically.The question also is ,why a vocher?can't they refund our money,because we did not cancel on our own accord,It was by Presidential decree.We are not happy at all!!