Denied boarding

My daughter and I booked a flight with British Airways from Johannesburg to Dublin. This was departing on 22 December and arriving the following morning. The seats were both Business Class and there was a connection in London. Boarding passes we’re issued for both flights. When we got to the gate of the London to Dublin flight people were boarding. However, we were denied on the basis that the computer thought we would not make it. No effort was made to reinstate our reservation and the staff attitude was indifferent and unapologetic. As a result, we had to wait over two hours before we took off on another flight. I’m a loyal customer of GOLD status but really question BAs Bad Attitude. Today, my wife and 7 month old son, are also traveling business class, is connecting at Heathrow and BA had messed up her connection. Instead of departing at 07:20 her flight has been changed to 13:00.