SABC is stupid and inept

The SABC is *********** and *******. I sold my television set in 2007, and notified the SABC of such, provided proof to them and cancelled my license. They confirmed it was cancelled. Forward 15 years, and they now claim license fees since 2005. I must now find documents that I no longer have, as I was only required to keep them for 3 years (consumer act). I have to prove that i do not own a tv (I do not own a tv) and that I have not purchased a tv since 2007. How do you prove something you never did? The SABC is stupid!