Terrible service!

I returned the vehicle on the 5th May to Europcar in OR Tambo. A gentlemen came to inspect the car and signed me in. The next day I received an sms notification to say that damage was noted. I had to call into them and reached Prince Kagope who said apparently a dent was noted, however it definitely was not there when I handed in the car. Despite my biweekly follow ups, I have been ignored and a deposit is still being held. I have had a similar incident with Avis, and their communication and customer care was far superior. The lack of customer service and communication is shocking. I have called, emailed and have even put in an online complaint with no reaction.