ABSA created my bad credit score

After a submitted twice information that my salary will not be paid in on the 24th of December the deducted my personal loan payment from my account. Needless to say I did not have enough money in my bank for the transaction. When I phoned them the operator said I will be paying a penalty but when the payment is deducted at the end of the month the penalty will be paid back to me. But they just gave me a bad credit score and he just said yes that is now unfortunate not their problem. ABSA is not living up to their end of the deal when I signed the contract I confirmed that my salary will be paid in at the end of each month. So now I am getting a bad credit score. Thanks a lot ABSA.