Europe car poor service

On the 30th March 2023 i got involved in an accident and as part of my insurance cover i Got a car From Europcar which was arranged for me by my insurer as a curtesy car.i got there and Paid an amount of R2000.00 as a deposit which i didnt have a problem with.arround the 10th April or so,i cant remember the date i got a call from an agent from Europ car that i need to return the car at any Europe car Branch because the car is almost due for service and they will issue me with another car.as directed by one of their agents i did so and i took the car to Europe car OR Tambo,Just when i was at or Tambo Europe car my insurance informed me that my claim has been approved so i need to fully return the car.i informed the agent that was helping me tbat My insurance will no longer be responsible for my rental and i will take over and pay for myself.i have already paid a deposit from my pocket,can i pay a rental for the next coming 2 weeks with polo,they quoted me on a polo and there were no hidden fees that i was told about.everytime i extend my days i paid upfront.now suddenly i am being informed that i ower over R6k from their hidden fees which includes me changing from a car that was selected by the insurance when i take over the account and Dropping off a car at a different branch which is what they instructed me to do.