Booking cancellation because of their system error

I booked a flight with FlySafair yesterday 10/12/2023 with the option to pay later, I recieved a booking confirmation with a booking reference and the payment due date of 10:59 am However as I was trying to pay for my booking at 10a.m the system cancelled my booking. I have tried numerous times to engage them 3 times and they keep me on hold for more than 40 min. I was told that the confirmation which was 10:59 due date was incorrect but still, they can't assist with reinstating my booking. I am very disappointed with FlySafair. Booking ref 47Y2UD