Conned by Avis car rental

There is a tendency of seeing other dents besides those marked on paper. The trick with dents is some are just not visible, and we innocently check the visible ones and then rely on the inspectors to do the rest, however I have noticed a trend with East London Avis, most returns there is that dent that will be shown to you. I I have 2 disappointing incidents, addition is the incident on that happened on the 6th of July. It really makes one wonder about a lot of issues, I was not the only person who returned the car and there was that dent noticed. We are schemed by Avis. Wonder if the panel beaters can tell the dent age, I think it can help.