Unfair wait for money that is actually the customer's

It is ridiculous that you are forced to wait (and accept before you can hire a car) 7 days for your deposit to be released to you after the rental company has received their car. Its the 21st century and there are and means already devised to subtract what needs to be subtracted so that on delivery of the vehicle by the customer, they can get their deposit back as well. If we can do it at other companies then why cant Avis/Budget car hire get with the times and not make people wait for what is rightfully theirs? Pathetic!