Autobell Car Wash

Took car for a $4 wash. Mid-way thru cycle, car lurches and begins to back up. I hear 3 booms as my car is jolted. Cycle begins again. On exit I get out and see a huge dent in my driver's side rear panel. An employee came out after I motioned for him and the manager soon followed. They wrote up a claim and told me they had never seen such a thing and suggested that perhaps the dent was already there. My car is 15 years old with less than 12,000 miles on it -- so it has been babied. It was not dented. After meeting with the district manager on Monday, he told us that he could not see how the dent could have been made and said that Autobell would not be responsible. He gave me an address for legal correspondence. Been going to this same location over 10 yrs and always been satisfied. It is never good to call your customer a liar either outright or in veiled terms. This is not good customer service, and, as you must already know, I will go out of my way to tell everyone.