ITC listed

I made a payment of the outstanding amount which I paid late last year and was not aware was outstanding, cause the last call I made to Cell C I was advised I owed some few cents (not more than R1) which I paid I think in October or September last year if I am not mistaking however I noticed that Cell C blacklisted me and still haven't updated that I made a payment. This is really affecting me as I my loan was declined due to that and this is really frustrating. I need this matter resolved immediately.