GotoGate not refunding cancelled tickets

I booked a flight ticket for my son to fly from the UK to SA in April 2020, due to the Covid pandemic the airline Swuss air advised that they will give us a voucher to rebook the ticket for a later date. We then booked the ticket for December 2020 and recieved an email from GotoFate that the flight and ticket was cancelled with no explanation no refund or no voucher. Until today i am trying to find out about a refund but I am not getting any response from GotoGate. Swiss Air advised that it is out of their hands as the agency GotoGate has to send the refund request which has not been done I assume as I still don't have my money back. I now had to book another ticket for my son with a different airline and definitely not using GotoGate. Refund refunding no. L3Q5QH.