harrassment from attorneys, rude staff

I have been harrassed constantly by the collections department of these attorneys who are extremely rude for non -payment of my tv licence. My tv licence is paid every year and I send proof of payment to the SABC every year. I have queried additional charges from the SABC for the last 6 years and the SABC never responds. I have emails confirming this and disputing any liability for additional charges. I have advised the collections agents of this countless times and yet they still call me 3 or 4 times a day. In fact, just this morning I received 2 calls, both before 8h00 and within the space of 30min and this after I told the lady to sue me and that I would be suing them for harrassment and sending a complaint to the law society. They also do not have any attorneys dealing with the matter who I can speak to and I have told them countless times to sue me and have even given them the address for which they can send the summons. My next step is to report them to the law society and to obtain an interdict againt them to stop them from harrassing me.