Ridiculous vehicle finance department debit order change refusal

I PURCHASED A VEHICLE WITH ABSA AND THEY CHOOSE THE WRONG DEBATE ORDER DATE SO I CALLED IN AND THEY REQUESTED I SEND A SALARY SLIP WHICH I DID AND ALSO A LETTER FROM MY EMPLOYEE STATING 10TH OF EVERY MONTH . MY COLLEGUE ALSO PURCHASE A VEHICLE AROUND THE SAME TIME AS WE WORK TOGETHER IN THE SAME COMPANY . HE WAS SUCCESSFUL IN CHANGING HIS SALARY DATE BUT WHEN I HAD SENT THE REQUEST THEY REFUSED TO DO SO DESPITE ME SENDING THE SAME LETTER FROM OUR HR . THEY REFUSE TO CHANGE MY DEBIT ORDER DATE. NOW I AM GOING TO HAVE AN UNPAID DEBATE ORDER JUST BECAUSE OF THE RIDICULOUS VEHICLE FINANCE DEPARTMENT THAT REFUSED TO CHANGE MY DEBIT ORDER DATE TO THE 10TH OF MAY 2023. THIS DEPARTMENT IS ABSOLUTELY UNREASONABLE WITH THERE CLIENTS. HOW CAN YOU CHANGE ONE DEBAT ORDER BUT NOT THE OTHER YET WE PURCHASED IN THE SAME MONTH