Europcar - None return of car rental deposit

On the 11th of Jan my family rented a vehicle from Europcar under booking ref ********** 89 and returned the vehicle on the 15th of Jan. We paid a deposit of close to R5800 in total. On return of the vehicle on the 15th of Jan we were advised that we would receive our deposit after 3 working days. To date we have not received our deposit back but just a statement indicating that we will be getting R4700 deposit and numerous deductions. We have placed over 15 calls and been referred to amongst a whole chain of useless people a Craig van Niekerk who is never around but just leaves his answering service on to take messages.