Bad airline ethics

I had a flight from Cape Town International and was travelling with my 2 kids. Note that this was the last flight arriving in Johannesburg at 10.00 pm due to their delays that they were experiencing. One of our bags we were told we could not take into the plane and the checking in counter was closed. we were told to leave the bag behined. I had to let my son stay behined with the bag. He had to take an uber back to Cape Town City. I have been trying yo get hold of Mango to get a refund for his ticket. Someone else on that same flight sat on his seat. I am still waiting for a response from Mango.