My mate purchased a VW Passat about 3 months ago from a small time car dealer, he got in contact with the previous owner and 100k miles have gone missing from the car!. The car has 80k on it and the last owner sold it with 175k on it!. The car is about 8 years old and is 1 previous owner. Basically what should he do? he has the autotrader with the original ad in and a full reciept.

Any idea?

Tito