Europcar not returning my rental deposit

<p>Rented a car from Europcar for a week. I returned it on the Saturday. I was promised 3 - 5 working days for the return of my deposit. The 5 working days are up, still haven't received my deposit, apparently my banking details wasnt captured on the system. When I returned the car the agent at the helpdesk was very abrupt and rude when I enquired if they can keep my deposit as I needed to rent a car the next week again. I am thinking that this was done on purpose. Very very poor service. Will never rent from them again.</p>