Unclosed Accounts

I have been having a problem with Cell C for the past 3months now, with them not closing x2 contracts I had with them in 2014 which is affecting my credit score as they have listed one of those accounts in arrears. I have called them and was assured the accounts are closed. A month later when checking my credit report the accounts are still active. Eventually I filed a dispute and the results came back with Trans Uionion closing the accounts as Cell C didn’t make contact while the dispute was being investigated and I thought Im in the clear as these accounts are messing up my credit score. I check my credit report again and Cell C has brought back these accounts. I am tired of holding 30+ miunutes for their legals department which is not helping at all as they don’t event reply to my emails. I am honestly without any idea of how I get get Cell C to resolve this matter. Cell C is just not helpful when you need them but miss a payment and they will call you immediately and close you line. I have been a Cell C client since 2008 and I am highly desapointed at how this is going on for so long without any assistance from them.