Cancelled Flight - No response from customer care

We booked 2 flights via Travelstart on Skywise for Tuesday 29 September from OR Tambo to Cape Town from 06:00 to 08:00 (S8 101). <br> <br> We received an email informing us that the flight was cancelled and that we had 2 alternatives to choose from for that day. The letter stated that one of the agents would give us a call or that if we haven't received a call that we should contact ***or ***, or email them.<br> <br> We phoned both those numbers, the one is always engaged and the other has problems with not working when you choose the options from the voice prompts. I then sent an email explaining my situation and that I need to choose a flight, to which I have had no response. I then phoned the ticket sales office at Cape Town International and asked if they could help me. They gave me *** to phone. I got through on this line but was cut off every time, once I managed to leave a message for someone to call me back, but still haven't received any response.<br> <br> It is now 14:10 and I still haven't had any response and still am unable to choose the alternate flight. I am not sure what to do next!<br> <br> <br> <br> <br> <br> <br> <br>