Deficient exhaust turbocharger

Hello everyone, yesterday we picked up our City Coupe smart & passion from the inspection and were pointed out that the exhaust turbocharger, or the associated dumpster has a crack. Since the vehicle is only three and a half years old, the manufacturer has declared himself willing to take part of the considerable costs, – but the part must now definitely be replaced. On demand, I was informed that the damage is not due to incorrect driving or e.g. I would be interested to know if this damage has already occurred with other smarts, or if someone knows if you can’t repair something like this (sweat). And how the manufacturer has behaved in other cases of culprits. I am grateful for any information! spechtin