Aveo 1.2 l gasproof ??

Moin, Moin I’ve been driving a Aveo 1.2 l car gas for 10 months. Every day 230 km. After now 47000 km of reasonable drive the valves have hung. Then the valves don’t close properly and the exhaust gas would burn the valves and the seats until the capital engine damage. It was repaired on culantness at no cost, but I think that happens again in 40000 km. Precautionarily have shown a gross lack at my dealer. It makes itself with dwindling performance and a I think I’m one of the first with a 1.2 l 16V Ecotec engine with such a high mileage with autogas. With the request for exchange.