KULULA.com - Unaccompanied minor

We booked flights for my nephew and niece for this morning from EL to Johannesburg. Their ages are 12 and 9 respectively and the booking went through successfully. Only for the 9 year old to be turned back at the check in counter this morning because according to your agents, she cannot be supervised by her 12 year old brother (whom is considered an adult by Kulula's booking policies by the way). Now one of them is back and the other still in EC and going to miss yet another day of school because they failed to stipulate that a 12 year old cannot travel alone with a child. On top of that, the evening flight is fully booked and we cannot get her on it with an "adult". Now we have to look for other means of transport because there are no validation checks on the Kulula website (if adult is > 12 years then proceed with booking, else decline). Now how are we to get my niece in Joburg in time for school tomorrow? and how will we get a refund for the mess up? my sister was told to write an email, but we all know it could take forever for that email to even be read? and what must happen in the meantime?