Cheated by the company?. Review on Fiat Linea

I own a linea petrol active. Got the delivery on 5th may, things went on smoothly and v liked our car very much and felt the admiring glances around. But the euphoria was extremely short lived as the car failed to get a registration no at the rto board because of the tampered chassis no.we cross checked it with all other lineas around. Tata motors had sold us a brand new car with overwritten and probably changed chasis no and did not even point it out to us. Now they are not owning the responsibility of tampering but it is very obvious for anyone to see. Can anyone advise on this. Everybody that we consulted said that either they have remodeled a damaged car or they have sold you an old model with changed chasis or its a theft car , etc.coming from a company of repute isn't it really shameful. Taking out an old car for the price of new from a branded and assigned showroom.

All the prospective buyers please please check your chassis no before taking the car home and compare it with other cars around..otherwise u might just land in legal hassles like we have!