Mis sold car finance ?

boomching

Hi all i bought a car in 2008 on finance and i still have 3 months worth of payments left, but upon putting it into get repaired by a bodyshop garage (for sill rust) i was told by the garage the car has had a whole new rear wing at some point and the finish on the sill where the front and rear wing meets was welded to a poor standard and thats why it had rusted over the years.
Now i was never told of this damage/repair and obviously i had not noticed it up until the point of the repair as i wasn't looking for damage as the company was nationally know and i trusted them.
Does anyone have any idea as to where i stand with the situation ? have i been mis sold the car as they did not tell me about the damage ? or more to the point am i to late as its almost paid up ?