Avis service is shocking

The service I experienced was absolutely shocking from Avis. I was told that if I ended up at the wrong place at 5am in the morning take car to Eurocar and that will be fine. I had a witness to this instruction. I then got a bill for another day as they said I returned the car after 2pm. I flew out of JHB at 6 15am that morning. They then contacted me and accused me of lies. Once I said I had a witness the discussion ended and they would not return my email. My next step is social media.