Chaotic 'service'

BA6226/10th May 2015 Durban to Johannesburg was part of a Qatar Airways booking to connect with QR1360 to Doha and then QR944 to Singapore. BA was delayed around 45 minutes with no indication that this would be a problem and my baggage was even booked right through to Singapore at the BA Durban check-in. Because of late arrival at Joburg, I and others were denied check-in for QR and subsequently rescheduled onto later flights by QR. As a result of all this, I had to buy a replacement flight from Singapore to Jakarta, where I had to be the following night, at an extra cost of SGD148.90 as later arrival at Singapore meant I had missed the flight I originally booked. QR's response: 'as the mentioned delayed flight BA6226/10th May 2015 was operated by British Airways, you are kindly requested to refer to them directly as they will be in a better position to address your concern.' Now BA KNEW there would be a delay hours in advance of the flight, so why did they not put connecting passengers on another flight to Joburg? Or coordinate with QR to get us quickly transferred to the QR connection at Joburg? And what about some compensation for the above loss because of all this?