ABSA Rewards Travel

I booked a flight for the 12th of April. It got rescheduled to the 14th of April. I have a deadline to be in the UK for the 13th of April. They have not been able to help me reschedule, only said after the 4th call that there are now magically new seats available, but at a penalty of an extra R14700 on top of the initial payment.