Paintwork problems

In March 2013 we took possession of a new Lunar Quasar from a local dealer, a few months later we noticed small bubble marks on a small area on the nearside paintwork. This turned out to be caused by air getting under the paint when originally done by Lunar. The defect was rectified by the dealer.    In September the same year the van was back in the dealers to have a new rail that holds the offside dinette table to the wall fitted, unfortunately the fitter used the wrong sized screws and they  pretruded through the outside wall, another repair and paint job.  In February 2014 the problem with the paintwork on the nearside reoccurred and again it was repainted by the dealer.  We have now discovered that the paintwork on both sites is starting to breakdown and will need repainting, in my opinion there appears to be a problem with either the paint that was used or the workmanship of the technician. Unfortunately the dealer refuses to accept any responsibility stating that to long has elapsed since the repairs.  Has anyone had any similar problems.