Frustrated !!!

I raised a dispute with Cell C last year in August. It has taken until May this year to have it resolved! In the interim they have reported me to Trans Union as being a slow payer, for an amount that I did not owe and has subsequently been credited. I have been trying in vain to get a letter from Cell C in order to clear my name, without success. In the interim I continue to get turned down for finance due to the report. I am left feeling totally helpless and frustrated. Perhaps the next step should be to stage a sit in at their local head office!!!