Credit Profile Mess Up

I had an account with Cell C which is currently closed but yet on my credit profile it shows that I have late payments for April and other past months but the account has been closed for over a year but on some credit bureaus it indicates that I owe about R1000 and on Clear score and Transunion it indicates the account is fully paid. This matter negatively affects my credit score. Cell C can't tell me why this is happening.