FlySafair not refunding as promised

I have booked tickets online on 2 November 2021. The website crashed and it said the payment didn't go through and my booking couldn't be confirmed. I had to log in and start the whole process from the beginning and then pay again. Then the previous booking came through as well, so I ended up with 2 bookings for the same flight for the same people. I immediately notified FlySafair, they have promised a refund and then went silent. It has been a month. I think this is a wonderful business plan for them, earning interest on other people's money.