They keep taking the deposit in error, and refuse to refund

I rented a car from 9-12 March at Tempest. I've already paid for it through a Discovery Travel booking. At this point they kept a deposit of R3620.00 on my credit card, which is normal. I returned the car without issue, on the 14th of March I received my refund for the deposit of R3087.30. As they kept ±R600 for refuelling etc, that is perfectly fine.

The money was then deducted again on the 16th of March, and reversed. on the 19th of April, the same thing happened, again R3087.30 was deducted from my account and reversed.

Now on the 26th of April, THEY DID IT AGAIN, but this time without reversing. R3087.30 has been taken from my credit card, when I've already paid for the booking and the extra.

Can you fix your accounting mess please and refund my money? My contract no. is ***