Fauty Coffee machine

My sister bought a £700 coffee machine from Gaggia last year and has had a few problems. Firstly the digital display mists up. She took it back and they sent it back to the manufacturer and they came back and said it was just condensation. The sa said they had had a problem with some machines but he thought he had sorted it out. She asked for a new machine but they said it was not company policy to replae them. Now the same problem has occured again and now the milk frother is also constantly leaking. She wants her money back and is wondering what her rights are?