Change co-payment on authorisation letter after I already made payment, which resulted now in an overpayment that I struggle to get back

My husband was admitted via the ER to the hospital on 12 Aug. Because an emergency procedure was also done, I had to make a total co-payment of R5490, which was R1830 for the admission and R3660 for the procedure. The hospital demanded that I made the payment otherwise they will not admit me. So I made the co-payment. Now afterwards when I requested my authorisation letter, the co-payment only states R1830 which means I paid too much to the hospital. I phoned the medical aid this morning and they said that they waived the co-payment of R3660, but the records were only adjusted on 26 Aug, which means that it has been changed after my the admission, in fact the co-payment was changed on the letter after my husband has been discharged. So now I don't have records from the medical aid that show the co-payment of R5490 that I paid. And I can't claim that back from the GAP cover because only R1830 is shown on the letter. Please note that this is my bread-money for the rest of the month that I need to urgently claim. You cannot change the records afterwards after I already paid. Who is going to refund me? The hospital said that my claim for the admission of 12 Aug has also not been paid yet. The hospital said that it is a levy that the medical aid ask so the medical aid must refund me. And I am sitting in the middle waiting for money that is due to me. Will you please change your records back to the original R5490 so that it corresponds to the amount I paid so that I can claim from my gap cover. My authorisation number is ***. My membership number is ***