Piston bore into short motor ssangyong wont fix it

Hi we have a dec 2006 rexton 31,000 on clock have owned it 10 mths and broke down on us garage said that piston has bore and needs new short motor they say it from oil starvation but we religiously checked oil and no oil light has ever displayed to indicate low oil garage has noted this in their report to ssangyong but because we have 1 service missing they will not fix this does anybody have any advice thanks..............................obviously got 4 mths left on original warranty plus they have already fixed a few problems already under warranty no problem!