Cell C is only causing me problems and don't do what they say they'll do.

Its been such a battle to get a paid-up letter from Cell C for my debt that I paid up long ago and when I eventually got the paid-up letter it said that my credit score will be cleared with the credit Bureaus between 2 and 21 days and it has been months now and still I can't apply for a home loan.

Please, please, please can someone just sort this ******* out?