Offered refund on cancelled flight and then retracted.

Booked 2 return flights from CT-JHB prior to Lockdown. Both were cancelled and we were offered choice of re-schedule or refund. Selected refund and were routed to a voucher application. Submitted application, got acknowledgement stating voucher would be issued shortly. After 2 weeks got a short email stating we were not eligible for a refund. no explanation. No response to my email to customer service asking for an explanation.. Both my wife and I are BA silver card holders. Seems loyalty is a one-way concept at BA.