4 strokes don't seize unless they was taking the cylinder out not much can be said to them in my experience blame manufacturer things like that should only happen once in a life time blocked grudgun pin or oil way. I can't let mine run without throttle as it also uses oil pump im afraid they would have to charge you for a block cylinder gasgits and labour expect £1000 at least plus that's could be classed as over heat or driver error good luck don't know if them parts are insured good luck