Billing issues

3 months ago, NuDebt acting on behalf of SABC sent me a deal around paying off my outstanding SABC Tv license balance. I agreed to 3 months debit order, I paid it up and got the letter that confirms that. After having done all of that, their callcentre still called me to say I need to pay and I have repeatedly said I have paid. This month, I got charged about R168, for what? I do not know. To top it all I got a letter from SABC telling me that I owe over R2000. And whilst they do not respond to my emails, today I got another letter saying I owe R1997. I no longer have the TV and all i wanted was to settle the debt and move on. I have emailed (both SABC and NuDebt) and no one has responded, I am beyond unhappy and feel that this will give me a bad record even though I have fulfilled my end of the deal.