Blaming me for an invisible dent

I appreciate getting an upgrade car but I do not appreciate being accused of making a dent on a car that is almost impossible to see and was there before. I asked the gentleman to write it on the checksheet and he said that he did. I took my own proof before as well as I have been told that rental companies do tend to do this sort of thing. Now I will have to wait a long time for you to release my deposit back to me. We will never rent from you again!