Enterprise Rent-A-Car Claim for Pre-Existing Damage Dallas, Texas

I rented a vehicle on 7/1 and returned it on 7/6.  It was a loaner vehicle from the car dealership while my daughter's car was in the shop.  The ERAC rep and myself did a joint inspection of the vehicle in the car dealership parking lot (not at the ERAC site), I pointed out a couple of dings on the door and the rep annotated them on the inspection sheet.  He asked me if I wanted the Optional Damage Waiver, I informed him that I did not need it because I had renters insurance with my provider.  I picked the vehicle up from the dealership parking lot and was told to bring it back to the same dealership and leave the keys with the customer service rep.  On that same day I received a call  informing me that there was damage to the vehicle stating that the bumper was ripped out.  When I arrived on site I looked at the vehicle and the side of the bumper cap was pulled away from the fender well so I pushed the bumper back into place and asked the lady what was the policy about the inspection of a vehicle.  She informed me scratches over five inches, dents or dings, and the bumper falling off.  I showed her where I had pushed the bumper back in and asked her if I were to inspect this vehicle right now as a consumer, how could I tell that the bumper was unservicable, she acknowledged that she understood what I was saying, but that she had already entered it into the system and informed me to contact Damage Recovery Unit.  She told me that a wrecker was on the way to pick up the vehicle, so I asked her if I could take pictures and she informed me that it was ok.  I received the Claim information letter on 7/19 informing me that a claim was filed against me for the bumper.  I called the DRU to find out what type of damage and the cost. The person answering could not give me the information that I requested, she informed me that the estimate and pictures were mailed out on 7/18 and I had to talk to the claim rep so she transfered me to the claim rep.  I was forwarded to the voicemail of the claim rep and I left my contact info (which I have yet to hear from).  I called back the next day , 7/20, and was told the same thing by a different person, she told me the same thing that I would have to talk to the claim rep, I told her that I keep getting the same voicemail response so she gave me the number to the office, which I still receive that voicemail with no reply.  I received the estimate, repair invoice and pictures today.  I called the DRU to talk to the claim rep and guess what?  Received the same voicemail.  I called the DRU main line again and was told that I had to talk to claim rep, I informed her that I have made numerous attempts and have not been able to get in contact with the rep, so she forwards me to a different rep who is able to view the claim.  I informed her that I had a dispute over one of the photographs that were sent to me, that it looked like there was more damage to the bumper on their picture versus mine.  She asked me "why would we do that?", (to fix a bumper that was already unservicable and to gloat that I should have taken the Damage Waiver for $20+ a day for a week!! Sorry for the emotional outbreak)  She told me that she had a photo that had an impact mark on the bumper that she was going to email me, still have not received it.  The bill was for $470 for a $15 dollar part and I have a $500 deductable, go figure.  After reading on this website with similar instances I truely believe that some dishonest business practices are going on and I do not intend to accept the charges for "Right side of bumper ripped out" which was not caused during my rental.