never pay for 2 rental cars on the same day with one credit card

On 26 June 2023, I rented 2 small cars from Tempest at George airport. The rental company took 2 deposits of R5820 for each of the 2 vehicles. The cars were returned on 1 July 2023. The following week, I received a credit for only one of the vehicles. After around 20 emails between Absa Disputes and Tempest, on the 28 August 2023, the 2nd credit R5820 was made to my account. On 27 September, an email was received from ABSA advising they are reversing the credit. Within that email, they state the 2 debit transactions and 2 credit transactions, which actually makes a mockery of their email. There just does not seem to be anyone at ABSA that can read and understand english. I realise it is not a normal transaction for one person to rent 2 alike cars on the same day, but that did happen with the appropriate proof provided.