service technician joyride in costumers car

I just bought a second hand rs265 2weeks ago and took the car to the Renault bryanston branch last week Friday to check the tyre pressure sensors which were faulty. I thought it was going to be a quick check so I decided to wait at the dealership. Once the check was complete, the techanican working on the car then took my car for a test drive. I’m sure he didn’t know I was at the dealership, since he speed off and accelerated very hard down William Nicol drive. I don’t appreciate others taking my car for a joyride.