Mango Airlines - Not honouring promises

I called Mango straight after Lock Down was implemented with regards to Ref# THCGBY to ask for a refund and was told that I could not get a refund but that a voucher would be issued within 7 days. I then sent an email to *** as a back up. To date I have received nothing. I tried to call the refunds number and held on the line for 40 minutes. No answer. I then tried the head office number on their website. The answering message says they are closed. I realise these are trying times, but technology provides means to communicate. This does not bode well for Mango going forward if they cannot even communicate with their customers or honour their promises. Not impressed.