Hyundai i10
2010 model instead 2011

I have purchased i10 on 8.02.2011 with the condition to deliver me 2011 model. I have not received its RC book whereas Insurence paper indicate model is after insisting I got xerox copy of RC book (after 5 months) which indicate year of manufacturing sept. Is it not a unfair buisness tact adopted by dealer? What should I do? I have installed CNG kit from same deale