No refund voucher for flights after numerous attempts

I have sent numerous emails to Mango airlines without any reply and phoned numerous times to just have the same annoying tune playing in my ears and after 30min no answer to my calls!!! We have made bookings to fly PE-JHB in August to see a concert. Obviously the concert has been canceled until next year with FULL refund and we already,let me add before the concert even got canceled, received flight vouchers from SAFAIR to use within the next year. But absolutely no response from Mango. It is super frustrating as it is not just R10 that can be written off. It is thousands of rands. I used to be a frequent Mango flyer as I preferred Mango above anyone else but I will NEVER EVER use Mango again nor will I advise anyone to do so. Sort this **** out!!! We have all been hit by financial difficulties due to Covid 19 but we had to battle through this on our own,so man up and do the same!!!!