Cancelled flights will not get refunded

BA cancelled flight in Dec 2020. Refund was promised in voucher firm by call centre. We are now 6 months down the line, 13 calls of which each is 40 min waiting time, and 16 email reminders. Conclusion is that they are just going in circles to avoid issuing any voucher. Head of call centre Keesha Regal is keeping to her empty promises