What recourse do I have in getting body work redone to my car?

I had some body work done to my car last August 2011. To be precise, I had my front bumper repainted because of peeling and chipping. The shop assured me that they could do the job. It cost 700.00 for the work. I recently notice the peeling and chipping happening again so I decided to return to the shop that did the work and ask him to take a look at the condition. He claimed that''s what happens when stones and bugs hit the vehicle. I told him that if that was the case everyones vehicle would look like mine. There was no altercation or arguing I just left and decided to give justice a try. Can you tell me if I have a good case.