Buderus GB172 Never Ending Problems, Ignition, Safety Valve and More

As soon as my Buderus GB172 reached the end of 3-year guarante, it started to have problems. First I had to get the ignition electrode set to be replaced since I got 9A227 code. A few days later, safety vane needed to be replaced, since it started to drool. Just a few more days later, there started to come water via drain mast continuously, and the repair guy said the aluminum heat exchanger block is leaking the water, and said it needed to be replaced, which costs almost half of a new product. Do I have to replace the whole device in every 3 year? What kind of a craftsmanship is this? Why do I have to choose Buderus next time? Who will replace my money, my time, my moral?