Auto pedigree

I bought a car in welkom auto pedigree 2017. . Sad part is that the car was involved in an accident. It is only after 3 years that the car's paint work started changing color on the rear bumper.the car petrol tank was glued as it was leaking and it started showing only after 18 months of purchase. I spoke to on one of the sales man and he referred me to the manager. And the manager asked sorry but very stupid questions. Like why am I reporting after so long . Started making accusations like I did it. And he said I should go to the car manufacturer they will tell me if the car was ever bought a new bumper . And I explained that it's your job as a dealership.he did not entertain my complain