IT problem and now I have to pay 200 rand more per flight

So last night I booked tickets to JHB but while I was in the process of paying it brought up a message saying "Your ticket was already booked". But no ticket was paid for etc. I tried to call the call centre, but as it was after hours so I had to wait till this morning. When I called them they acknowledged that there was an IT problem which is now fixed but said regrettably we now have to pay the updated prices... So Kulula blocks us from paying for tickets, and now we have to pay more...