Pay back my deposit- I have proof

It is disappointing how this company has dishonestly kept a major portion of our holding deposit. On 25 November 2022 I hired a vehicle from Thrifty OR Tambo, and we left the airport at 6pm. Upon return on 27 November, the vehicle was inspected by the same gentleman who handed us the keys. He checked the vehicle, and was happy with everything. To our surprise we have been paid only R1100 of the R7000 deposit we put down. I called the call centre 3 days ago to query this, i was told they deducted due to the following reasons: 1. we returned the car late, 2. we returned the car empty (no fuel), and 3. we exceeded the KMs by 44km. Firstly, we certainly did not return the car empty- we filled up at the airport!and we have photo's of the gauge as proof (because we were expecting such lies from the car hire company). Secondly, exceeding the KMs by 44km only works out to approx. R400 that should be deducted- as per the T&Cs stipulated. Lastly, we did not return the car late. We were at OR Tambo at 6pm, which is aligned with the time it was picked up. Since 3 days ago i am still waiting for the call centre agent to email me all the justification they have for deducting SO much from our deposit; which is all baseless. I want to be given all the documents they have, including the agreement so that i can share the photos and other evidence we have on our side. I will not allow to be ****** of our money by *****ed tactics of the company. Send me all the justification you have in writing- as spelled out by the call centre agent on the phone 3 days ago, so that i can show you that the reasons are baseless attempt at keeping our money. I am super disappointed in this car hire company! I actually cannot believe that you guys do this to try and make extra money off of our deposits. It is atrocious.