Threats from SABC for Teljoy TV license that was never cancelled

I rented a TV at Teljoy in 1997, cancelling in 1998 and returning the TV. I have not owned a TV license, or purchased a TV since then. The ONE TV we do have in our home was purchased by my husband, using HIS TV license. Since 2010 I've received threatening emails and smses from various collections agencies working for SABC demanding payment of a TV license I cancelled. I have sent affidavits, emails, spend so much money on phone calls, etc, but nothing. Different people every time. Just when I relax and think it's finally been settled, surprise they're back. The latest demand is R9000+. Eight years later and I'm still battling with them. What more must one do?