Kulula stonewalling and refuse to refund cancelled international British Airways flights!!!

In December 2019, we booked international flights for our family with British Airways through the Discovery/Kulula/Comair platform. These were Cape Town to London return flights and are operated by British Airways (not by Kulula/Comair). Following COVID, British Airways then cancelled these flights, after which we requested a cash refund. We initially received correspondence that our cash refunds were being processed but now nobody wants to refund the cancelled tickets and we are getting passed from pillar to post! British Airways international refers us to Comair, which responds by referring us to Discovery Vitality through automated emails. I can understand how Comair could refuse to refund domestic flights that they operate, given that they are under business rescue, but these are international flights that we have received British Airways tickets for. As for Discovery and Vitality, they should be hanging their heads for this shameless abandonment of their clients that have booked through their rewards program...