Is it so difficult to change a booking???

I booked and paid for accommodation at Pretoriuskop on 27 and 28 April 2016. <br> I need to cancel the date of the 28th of April and book accommodation at Satara camp on 30 April 2016. <br> I spoke to a consultant earlier but he did not even understand what I want to do. <br> Surely I am not the only person that ever tried to change a booking? <br> I am now trying to book BD2 at Satara rest camp on 30 April 2016 but not able to amend the existing booking online. <br> If I do a new booking I am required to make another payment, however, I would like to move the funds from the 28th to this new booking.What is so difficult reservations???? <br> I now probably lost the booking at Satara due to the amazing lack of customer service and assistance...