Concerns regarding Europcar practices and incompetence of staff

We rented a car from their Durban branch. While inspecting the car for damages, I pointed out all the scratches and took photos. The staff member assured me it was normal and I shouldn't worry. As occasional car renters, we always use Europcar and had never encountered a problem before. Upon returning the car at King Shaka Airport, the staff member checking it noted that there were no scratches marked on the paperwork. I promptly showed him the photos with timestamps, highlighting the previously repaired plastic bumper. He acknowledged it and asked me to write a statement, which I did. When I inquired about sending the pictures, he said it wasn't necessary. However, today I received an invoice for the damage. I'm unsure if this is due to staff incompetence or an attempt to **** customers, as similar incidents are reported in reviews on Hello Peter