Leaking gas

My friend bought a 9kg gas at Caltex Volksrust and when she got home it had some noise. We both assumed it was too full and opened it to let some gas out. It did not stop, she continued using it for about 3 or 4 days. The following day when she switched it on there was a big flame on the heater, still shocked at that, both gas and heater was on flame. She quickly poored water as she was scared her house was going to burn down. She then took the gas and heater to the garage to report the incident, the management agreed that the gas was indeed faulty. Now the problem is they don't want to replace the heater, they are running around and saying they can only replace the gas. Ofcourse the gas must be replaced but that faulty gas damaged the heater.