Deposit refund

Overall service is good. But when it comes to releasing the holding deposit it takes awfully long. I returned my rental vehicle 12 February and up to today I have not received my deposit back. Other charge for a windscreen chip was extra charged to my card, but the deposit is still on hold. Now my question is, isn't the deposit supposed to be used for windscreen chips or so. I mean what are the deposit used for then if it is not for this kind of charges. But none the less. When I want a rental vehicle I have to pay the deposit immediately or else I cant get the car but when I return the vehicle it is not released right away. I mean they can just as well release it straight way as these funds are obviously not used for minor damages or fuel charges. According to the manager at the branch it can take up to 21 days to be released. I mean seriously , you make me pay immediately but when I want it back I have to wait 21 days. That sounds a bit unfair. Who in todays time have R1750 just to be kept on hold for 21 days + rental period. That after already paid the rental amount. Seriously, this is unfair.