Discovery Vitality

I had flight bookings which were canceled due to COVID. 4 and a half years later, I still have not received a refund. I continuously follow up with Discovery and I am told there is nothing they can do to assist in getting the refund, I must just wait for BA. When we wanted to use our vouchers we were told we had to wait for a refund. We have subsequently had to pay out for flights in order to visit our daughter in the UK. We are pensioners and really need the refund.