ENGINE MOUNTING BREAKING FOR THE FOURTH TIME

My husband purchased my vehicle 17 months ago(August 2013) with and extended warranty from Durban South Toyota( DST-Amanzimtoti). In January 2014 the engine mounting broke as well as the ignition mechanism. My husband went back to the Dealership and he was instructed to take the vehicle back to Bosch where they had repaired it originally, as he was informed that the engine mounting had been repaired just before we took ownership of the vehicle in August 2013. Bosch repaired the vehicle at the Dealerships cost. Within 6 months the exact same part broke. My husband went direct to Bosch this time and they repaired it. When he queried if they were fitting inferior parts because the same part kept breaking, he was reassured that the parts are original VW parts. 2 weeks ago, almost 6 months later since the last incident, the same problem occurred. My husband took the vehicle to the mechanic and was informed that the same side engine mounting was broken again. He then took the vehicle back to Bosch, this being the 4th time in 17 months. They are now refusing to fix the vehicle and have now claimed the dealership(DST) advised them to fit inferior parts to save money.