In July of 2016, my wife and I traveled to Texas. We found what we thought was a good deal on a rental car from SIXT Rental. The car was to be picked up and returned at the Dallas airport. On the day we returned the car returned the car the traffic was terrible due to a tragic shooting that had occurred in the city. We were preparing to leave when the gentleman from SIXT, stated the car had been in a collision and I needed to sign a paper he handed me. We inspected the area of the damage on found a very small black mark on the rear bumper the mark was less than a centimeter in length and diameter. It was the size of a small fly and appeared to be a smudge. I told him there was no collision, no scratches, no dents, just a small mark which had to be closely looked for in order to be found.He had difficulty speaking English and kept repeating the same phrase, you had a collision sign he paper. Even though we were running late due to the traffic, I went to the service desk and waited to speak to someone. The lady was very polite. I explained what had occurred and she went to her computer. After searching for an extended period she stated, “Everything is ok.” I asked her for reassurance and she once again stated everything was fine. We raced to the shuttle and barely made our flight.In October, I received a letter from SIXT claiming I owed $1068. I was asked to fill out papers regarding the collision and “damage”. I explained what happened at the airport and the absence of any collision. I asked someone to please investigate the claim, the amount of the cost, which included four days of rental, that the car was “out of order”. The cost of the spot was over $600. The mark as so small it could have been covered up with a dab of model paint. I did not receive a reply only a demand for payment. I sent four letters asking someone to please review the claim. After my fourth request, I finally received a response from SIXT. I got four separate form emails, which were not specific to my claim. The emails were general in nature and stated only damage was discovered and I owe the money.They were kind enough to allow me to pay over time. Upon researching, I found similar stories of rushed senior customers who after returning cars were notified by mail they owed money. A lack of personal communication was also a common factor. I cannot verify the veracity of their claims. I did find a consumer report that noted the average cost of repairs for damaged rentals was significantly higher for SIXT than any other rental car companies.I will avoid lesser known rental companies in the future. I will allow extra time to thoroughly inspect every inch of a rental car and note any small mark, scratch or any anomaly. I will further do some research before I accept any rental offers which appear to be great deals for seniors.