Disapointed in Rotax

I had a #2 upper left head bolt back out about 1/2 inch. This allowed the head to skew and the piston eventually rubbed the side long enough to wear through the side of the cylinder and allow the coolant to enter the cylinder. RUINED ENGINE.

The replacement engine, with the new spark plugs ($$$) blew the guts right thru the end. This happened in flight. The engine shook so violently that the muffler was shattered. It pulled the exhaust tubes right out of the muffler and even broke the muffler attachment right off. When the head was removed there was no damage to the cylinder or head. All of the material was blown out through the end of the spark plug. The porcelain was in perfect shape. No cracks. It just blew through the end! 

I don't know how to report this to Rotax and would appreciate any help. Has anyone else had any of these problems?