I took my car in for repairs, came back scratched

I took my car in for repairs at Alberton big BMW motor repairs on the 2nd of December 2015. A week before, my car was accessed by both my insurance and their repair assessors and no scratched were found and both of the took photos of my car. I brought the car in on the 2nd December 2015. When i went to fetch my car, I realized that my car had scratches on the boot. I asked how it happened and they became arrogant and defencive. The showed me the photo that was taken on the 3rd of December 2015 with scratches on my car. Then they said they will ask for the photos from my assessor and if the are no scratches they will fix my car. Surprisingly this morning i was told that they have received the photos from my assessor but they were not clear enough so they cant see if the car had scratches or not. So they say they cant fix my car because they cannot see scratches.