Avis car rental

Beware of Avis. Received car a ORT airport, did not get a form indicating marks, scrathes or no scrathes.I checked car at airport and could not find any marks but did not check the rear bumper underneath.With return of the car to Avis Montana I was informed there are several marks underneath the rear bumper and I will be invoiced for it.I received the car at ORT, drove to Pta and returned the car the following morning.I was not involved in any accident nor did I reversed into any object.I do feel marks and scrathes are missed with car returns to ORT due to poor lighting and the time limit with cars streaming in.The person renting a car from ORT then become the person to pay for the marks not picked up.Second time this has happened to us and definitely our last time with Avis.I have noticed on social media that I am one of many who has had a similar experience with Avis.STAY AWAY FROM AVIS.