I have just noticed that the rear passenger door of my car has some scratches on it, the marks seem to be done by the door of another car adjacent to mine - which I am sure has been from the neighbour's car. I live in a block of flats and park in the residential parking. What should I do now? It might have been a few days or probably couple of weeks since it happened and i have noticed it late. Should I just keep mum as nothing can be proved now?