Kulula won't answer any form of communication

We have made a booking for flights from JHB to Cape town and we where not able to book return flights because the system did not allow us to. Due to those reasons we booked 2 one way flights but did not notice the return flights was the wrong direction. We are trying to change the flights that is on the 10th of October but the system won't allow us and we have been holding on to the call center for 2 hours with no luck...... There is simply no way of communicating with them!!!!