Blacklisted for missing one payment!!!

In December last year my husband wanted to cancel our ADSL line with Telkom as we were moving to a smaller package with them. You had to give 30 days notice as he did with emailing them to cxl. The line never got cancelled by Telkom so my husband refused to pay as they made the mistake by not cxl the line.So now we where one month in the rears with them. Somehow they blacklisted us with ITC because of this. The small package didn't work for us so we decide to reconnect the line. My husband was then informed we were in the rears so the line could not be re-connected he paid the R400 over to get the line connected again. We needed to get a loan for something and now they won't give it to us because of this issue with the ITC. When we phoned the ITC they told us there is a black mark now against us because of this but we are paid up to date on there side. How the hell do you blacklist someone for a mistake you made we have always had a perfect credit record. Now according to ITC this will only clear away in 2 years time. This is unacceptable TELKOM!!!