Cell C doesn’t close accounts with Credit bureau after paying up or closing contract.

I had a contact with cell c, i paid it up and cloe the account this year January, paid in full. They closed the account on Trans union and forget to close it on Experian, now i need to apply for a house i cant get approval because cell c didn't close the account on Experian, i can't get any credit. Please help me rectify this. Please i paid it in full on January, now it shows owing from January with an amount of about R5600. Please cell c