Nudebt SABC Debt Collectors harassing me

Nudebt has been harassing me by phone, email and sms for months, claiming I owe SABC for a TV license. I've sent them 4 emails with proof I don't own a TV and cancelled my last license in 2012, yet I keep getting more sms's and emails telling me to pay or I will be penalized. It really is very frustrating that in spite of doing the right thing and replying to them with appropriate information, that they simply ignore that and keep harassing you!