Ignore it. That debt has become prescribed 7 years ago.
The burden is also on them to prove that you owe them the amount and that you have failed to pay your TV license at that stage.
Even if they want to charge you criminally they cannot do so. The statute of limitations for this is 20 years, meaning that the last year within which they could charge you criminally past some 17 years ago.
Have an attorney write a letter on your behalf, or do it yourself, in which you state that you categorically deny the allegations contained in the letter, that if they stand by the contents of the letter, they are welcome to try and prove it in a civil court and that you will defend all legal action against you and ask for a special cost order.
Inform them that any attempt at listing you at any credit bureau will be met with a claim for defamation of character.
Also inform them that you will not entertain any further communications from them and that any attempt to contant you again will be met with an application for an interdict in terms of the Protection from Harassment Act.
I hope this helps you a little bit, but if you have any further questions, feel free to ask them before you rate. It will not cost you anything extra. If you are satisfied with the answer, kindly click on one of the five faces on the ratings page. I don't get anything for this answer unless you do.