Change of departure gate nr, caused so much loss

My daughter was left behind at Beijing, after being at the departure gate, only for Cathy to change the gate nr... She was traveling alone and no one could help.. I sent SA offices emails on the same day and a later date... but still no response Cathy HQ has offered her a 100 dollars for her inconvenience.. but not to refund the ticket she had to buy to return home... and sleep over at the airport... She lost about R10 000 due to the change of gate... I find this very unfair...