Disrespectful, stubborn and rude service provider

I received a call from some debt collectors claiming I owe money to the SABC, lady called Wisani. Lady was rude from the beginning and spoke to me like I was a child. She claims I owe R318. When I enquired on how I was invoiced I was told I was sent an sms to a number I do not know. When I advised that it wasnt my number and my number is the one she called me on she got rude and interrupted me. I have never been invoiced and yet I am being taken to debt collectors, How does that work? I have always paid my TV licenses upon receipt of my invoice. I have never been this disrespected for R318 in my life. These personnel must learn client management and realise that they are dealing with clients and not some rowdy kids. I recommend training to ensure proper client interaction. I am a professional and refuse to be treated any lesser, I wouldn't do that to anyone else.