False Negative Credit report sent to Credit bureau

I paid my monthly installment at one of the fochini group stores at forrest Hill Mall. The person helping me captured the amount in the wrong payment plan and the credit department sent a negative credit report to the Credit Bureau. The amount I paid was above my agreed monthly installment and I paid on the 26th of June , whereas the final date of Payment was the 1st of July. I have tried to contact the credit department to clear my name but I was only sent a letter saying my account is up to date when the issue was resolved. But the negative report sent to ITC and Experiant has not been retracted. I just want my name cleared!!!